Change search
Refine search result
12 1 - 50 of 55
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1. Ahlvik, P
    et al.
    Karlsson, Hans
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Åsman, P
    Exhaust emissions from flexi-fuel light-duty passenger cars fuelled by petrol (E5) and bioethanol (E70, E85) tested at ambient temperatures of +22°C and -7°C: Part 1:Regulated and particulate emissions.2008In: Proceedings of the17:th International Symposium on Alcohol Fuels, 2008Conference paper (Other academic)
  • 2.
    Ahmed, Trifa M.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ahmed, Baram
    Aziz, Bakhtyar K.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Native and oxygenated polycyclic aromatic hydrocarbons in ambient air particulate matter from the city of Sulaimaniyah in Iraq2015In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 116, p. 44-50Article in journal (Refereed)
    Abstract [en]

    The concentrations of 43 polycyclic aromatic hydrocarbons (PAHs) and 4 oxygenated PAHs (OPAHs) are reported for the first time in particulate matter (PM10) sampled in the air of the city of Sulaimaniyah in Iraq. The total PAH concentration at the different sampling sites varied between 9.3 and 114 ng/m(3). The corresponding values of the human carcinogen benzotalpyrene were between 0.3 and 6.9 ng/m(3), with most samples exceeding the EU annual target value of 1 ng/m(3). The highly carcinogenic dibenzopyrene isomers dibenzo[a,l]pyrene, dibenzo[a,e]pyrene, dibenzo[a,i]pyrene and dibenzo[a,h]pyrene constituted 0.1-0.4% of the total PAH concentration. However, when scaling for relative cancer potencies using toxic equivalency factors, a benzo[a]pyrene equivalent concentration of dibenzo[a,l]pyrene equal to that of benzo[a]pyrene was obtained, indicating that the contribution of dibenzo[a,l]pyrene to the carcinogenicity of the PAHs could be similar to that of benzo[a]pyrene. A high correlation between the determined concentrations of the dibenzopyrene isomers and benzo[a]pyrene was found, which supported the use of benzo[a]pyrene as an indicator for the carcinogenicity of PAHs in ambient air. The total concentrations of the four OPAHs, 9,10-anthraquinone, 4H-cyclopenta[def]phenanthren-4-one, benzanthrone, and 7,12-benz[a]anthraquinone, varied between 0.6 and 8.1 ng/m(3), with 9,10-anthraquinone being the most abundant OPAH in all of the samples.

  • 3.
    Ahmed, Trifa M.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Emissions of particulate associated oxygenated and native polycyclic aromatic hydrocarbons from vehicles powered by ethanol/gasoline fuel blendsManuscript (preprint) (Other academic)
  • 4.
    Ahmed, Trifa M.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Emissions of particulate associated oxygenated and native polycyclic aromatic hydrocarbons from vehicles powered by ethanol/gasoline fuel blends2018In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 214, p. 381-385Article in journal (Refereed)
    Abstract [en]

    Emission factors for oxygenated polycyclic aromatic hydrocarbons (OPAHs) and PAHs have been determined from two different fuel flexible light duty vehicles operated at -7 degrees C in the New European Driving Cycle (NEDC) and at +22 degrees C in the Artemis Driving Cycle (ADC). Three different gasoline/ethanol blends, commercially available in Sweden, were tested i.e., gasoline E5, with 5% v/v ethanol and ethanol fuel E85 with 85% v/v ethanol and winter time quality E70 with 70% v/v ethanol, respectively. The results showed greatly increased emissions of both OPAHs and PAHs at cold engine start conditions (-7 degrees C in the NEDC) compared to warm engine start (+ 22 degrees C in the ADC). For the OPAHs, higher average total emission factors were obtained when running on E85 compared to E5 at both cold 2.72 mu g/km vs 1.11 mu g/km and warm 0.19 mu g/km vs 0.11 mu g/km starting conditions with the highest emissions when using E70 at -7 degrees C 4.12 mu g/km. The same trend was found for the PAHs at cold engine start with higher average total emission factors when using ethanol fuel 71.5 mu g/km and 60.0 mu g/km for E70 and E85, respectively compared to gasoline E5 (20.2 mu g/km). Slightly higher average total PAH emissions were obtained when operating at + 22 degrees C with E5 compared to with E85 1.23 mu g/km vs 0.72 mu g/km.

  • 5.
    Ahmed, Trifa M.
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Åberg, Magnus
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Determination of oxygenated and native polycyclic aromatic hydrocarbons in urban dust and diesel particulate matter standard reference materials using pressurized liquid extraction and LC-GC/MS2015In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 407, no 2, p. 427-438Article in journal (Refereed)
    Abstract [en]

    The objective of this study was to develop a novel analytical chemistry method, comprised of a coupled high-performance liquid chromatography-gas chromatography/mass spectrometry system (LC-GC/MS) with low detection limits and high selectivity, for the identification and determination of oxygenated polycyclic aromatic hydrocarbons (OPAHs) and polycyclic aromatic hydrocarbons (PAHs) in urban air and diesel particulate matter. The linear range of the four OPAHs, which include 9,10-anthraquinone, 4H-cyclopenta[def]phenanthrene-4-one, benzanthrone, and 7,12-benz[a]anthraquinone, was 0.7 pg-43.3 ng with limits of detection (LODs) and limits of quantification (LOQs) on the order of 0.2-0.8 and 0.7-1.3 pg, respectively. The LODs in this study are generally lower than values reported in the literature, which can be explained by using large-volume injection. The recoveries of the OPAHs spiked onto glass fiber filters using two different pressurized liquid extraction (PLE) methods were in the ranges of 84-107 and 67-110 %, respectively. The analytical protocols were validated using the following National Institute of Standards and Technology standard reference materials: SRM 1649a (Urban Dust), SRM 1650b (Diesel Particulate Matter), and SRM 2975 (Diesel Particulate Matter, Industrial Forklift). The measured mass fractions of the OPAHs in the standard reference materials (SRMs) in this present study are higher than the values from the literature, except for benzanthrone in SRM 1649a (Urban Dust). In addition to the OPAHs, 44 PAHs could be detected and quantified from the same particulate extract used in this protocol. Using data from the literature and applying a two-sided t test at the 5 % level using Bonferroni correction, significant differences were found between the tested PLE methods for individual PAHs. However, the measured mass fractions of the PAHs were comparable, similar to, or higher than those previously reported in the literature.

  • 6.
    Ahmed, Trifa M.
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Lim, Hwanmi
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Automated clean-up, separation and detection of polycyclic aromatic hydrocarbons in particulate matter extracts from urban dust and diesel standard reference materials using a 2D-LC/2D-GC system2013In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 405, no 25, p. 8215-8222Article in journal (Refereed)
    Abstract [en]

    A multidimensional, on-line coupled liquid chromatographic/gas chromatographic system was developed for the quantification of polycyclic aromatic hydrocarbons (PAHs). A two-dimensional liquid chromatographic system (2D-liquid chromatography (LC)), with three columns having different selectivities, was connected on-line to a two-dimensional gas chromatographic system (2D-gas chromatography (GC)). Samples were cleaned up by combining normal elution and column back-flush of the LC columns to selectively remove matrix constituents and isolate well-defined, PAH enriched fractions. Using this system, the sequential removal of polar, mono/diaromatic, olefinic and alkane compounds from crude extracts was achieved. The LC/GC coupling was performed using a fused silica transfer line into a programmable temperature vaporizer (PTV) GC injector. Using the PTV in the solvent vent mode, excess solvent was removed and the enriched PAH sample extract was injected into the GC. The 2D-GC setup consisted of two capillary columns with different stationary phase selectivities. Heart-cutting of selected PAH compounds in the first GC column (first dimension) and transfer of these to the second GC column (second dimension) increased the baseline resolutions of closely eluting PAHs. The on-line system was validated using the standard reference materials SRM 1649a (urban dust) and SRM 1975 (diesel particulate extract). The PAH concentrations measured were comparable to the certified values and the fully automated LC/GC system performed the clean-up, separation and detection of PAHs in 16 extracts in less than 24 h. The multidimensional, on-line 2D-LC/2D-GC system eliminated manual handling of the sample extracts and minimised the risk of sample loss and contamination, while increasing accuracy and precision.

  • 7.
    Avagyan, Rozanna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Nyström, Robin
    Boman, Christoffer
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Determination of hydroxylated polycyclic aromatic hydrocarbons by HPLC-photoionization tandem mass spectrometry in wood smoke particles and soil samples2015In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 407, no 16, p. 4523-4534Article in journal (Refereed)
    Abstract [en]

    A simple and fast method for analysis of hydroxylated polycyclic aromatic hydrocarbons using pressurized liquid extraction and high performance liquid chromatography utilizing photoionization tandem mass spectrometry was developed. Simultaneous separation and determination of nine hydroxylated polycyclic aromatic hydrocarbons and two hydroxy biphenyls could be performed in negative mode with a run time of 12 min, including equilibration in 5 min. The calibration curves were in two concentration ranges; 1-50 ng/mL and 0.01-50 mu g/mL, with coefficients of correlation R (2) > 0.997. The limits of detection and method quantification limits were in the range of 9-56 pg and 5-38 ng/g, respectively. A two-level full factorial experimental design was used for screening of conditions with the highest impact on the extraction. The extraction procedure was automated and suitable for a large number of samples. The extraction recoveries ranged from 70 to 102 % and the matrix effects were between 92 and 104 %. The overall method was demonstrated on wood smoke particles and soil samples with good analytical performance, and five OH-PAHs were determined in the concentration range of 0.19-210 mu g/g. As far as we know, hydroxylated polycyclic aromatic hydrocarbons were determined in wood smoke and soil samples using photoionization mass spectrometry for the first time in this present study. Accordingly, this study shows that high performance liquid chromatography photoionization tandem mass spectrometry can be a good option for the determination of hydroxylated polycyclic aromatic hydrocarbons in complex environmental samples.

  • 8.
    Avagyan, Rozanna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Nyström, Robin
    Lindgren, Robert
    Boman, Christoffer
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Particulate hydroxy-PAH emissions from a residential wood log stove using different fuels and burning conditions2016In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 140, p. 1-9Article in journal (Refereed)
    Abstract [en]

    Hydroxylated polycyclic aromatic hydrocarbons are oxidation products of polycyclic aromatic hydrocarbons, but have not been studied as extensively as polycyclic aromatic hydrocarbons. Several studies have however shown that hydroxylated polycyclic aromatic hydrocarbons have toxic and carcinogenic properties. They have been detected in air samples in semi urban areas and combustion is assumed to be the primary source of those compounds. To better understand the formation and occurrence of particulate hydroxylated polycyclic aromatic hydrocarbons from residential wood log stove combustion, 9 hydroxylated polycyclic aromatic hydrocarbons and 2 hydroxy biphenyls were quantified in particles generated from four different types of wood logs (birch, spruce, pine, aspen) and two different combustion conditions (nominal and high burn rate). A previously developed method utilizing liquid chromatography photo ionization tandem mass spectrometry and pressurized liquid extraction was used. Polycyclic aromatic hydrocarbons were analyzed along with hydroxylated polycyclic aromatic hydrocarbons. The hydroxylated polycyclic aromatic hydrocarbon emissions varied significantly across different wood types and burning conditions; the highest emissions for nominal burn rate were from spruce and for high burn rate from pine burning. Emissions from nominal burn rate corresponded on average to 15% of the emissions from high burn rate, with average emissions of 218 mu g/MJ(fuel) and 32.5 mu g/MJ(fuel) for high burn rate and nominal burn rate, respectively. Emissions of the measured hydroxylated polycyclic aromatic hydrocarbons corresponded on average to 28% of polycyclic aromatic hydrocarbons emissions. This study shows that wood combustion is a large emission source of hydroxylated polycyclic aromatic hydrocarbons and that not only combustion conditions, but also wood type influences the emissions of hydroxylated polycyclic aromatic hydrocarbons and polycyclic aromatic hydrocarbons. There are few studies that have determined hydroxylated polycyclic aromatic hydrocarbons in emissions from wood combustion, and it is therefore necessary to further investigate the formation, occurrence and distribution of these compounds as they are present in significant amounts in wood smoke particles.

  • 9.
    Avagyan, Rozanna
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Sadiktsis, Ioannis
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Tire tread wear particles in ambient air—a previously unknown source of human exposure to the biocide 2-mercaptobenzothiazole2014In: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 21, no 19, p. 11580-11586Article in journal (Refereed)
    Abstract [en]

    Urban particulate matter (PM), asphalt, and tire samples were investigated for their content of benzothiazole and benzothiazole derivates. The purpose of this study was to examine whether wear particles, i.e., tire tread wear or road surface wear, could contribute to atmospheric concentrations of benzothiazole derivatives. Airborne particulate matter (PM10) sampled at a busy street in Stockholm, Sweden, contained on average 17 pg/m3 benzothiazole and 64 pg/m3 2-mercaptobenzothiazole, and the total suspended particulate-associated benzothiazole and 2-mercaptobenzothiazole concentrations were 199 and 591 pg/m3, respectively. This indicates that tire tread wear may be a major source of these benzothiazoles to urban air PM in Stockholm. Furthermore, 2-mercaptobenzothiazole was determined in urban air particulates for the first time in this study, and its presence in inhalable PM10 implies that the human exposure to this biocide is underestimated. This calls for a revision of the risk assessments of 2-mercaptobenzothiazole exposure to humans which currently is limited to occupational exposure.

  • 10.
    Avagyan, Rozanna
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Sadiktsis, Ioannis
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Thorsen, Gunnar
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Östman, Conny
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Determination of benzothiazole and benzotriazole derivates in tire and clothing textile samples by high performance liquid chromatography-electrospray ionization tandem mass spectrometry2013In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1307, p. 119-125Article in journal (Refereed)
    Abstract [en]

    A high performance liquid chromatography–tandem mass spectrometry method utilizing electrospray ionization in positive and negative mode has been developed for the separation and detection of benzothiazole and benzotriazole derivates. Ultra-sonication assisted solvent extraction of these compounds has also been developed and the overall method demonstrated on a selected clothing textile and an automobile tire sample. Matrix effects and extraction recoveries, as well as linearity and limits of detection have been evaluated. The calibration curves spanned over more than two orders of magnitude with coefficients of correlation R2 > 0.99 and the limits of detection and the limits of quantification were in the range 1.7–58 pg injected and 18–140 pg/g, respectively. The extraction recoveries ranged between 69% and 102% and the matrix effects between 75% and 101%. Benzothiazole and benzotriazole derivates were determined in the textile sample and benzothiazole derivatives determined in the tire sample with good analytical performance.

  • 11.
    Avagyan, Rozanna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Target and suspect screening of OH-PAHs in air particulate using liquid chromatography- orbitrap high resolution mass spectrometryManuscript (preprint) (Other academic)
  • 12.
    Avagyan, Rozanna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Target and suspect screening of OH-PAHs in air particulates using liquid chromatography-orbitrap high resolution mass spectrometry2017In: Talanta: The International Journal of Pure and Applied Analytical Chemistry, ISSN 0039-9140, E-ISSN 1873-3573, Vol. 165, p. 702-708Article in journal (Refereed)
    Abstract [en]

    Up until now, the methods used for determination of hydroxylated polycyclic aromatic hydrocarbons in air particulate samples have been target methods, only determining compounds with available reference standards. In this present study, a combined target and suspect screening strategy for the analysis of hydroxylated polycyclic aromatic hydrocarbons was developed, utilizing liquid chromatography coupled to orbitrap high resolution mass spectrometry. The target screening included simultaneous determination of nine hydroxylated polycyclic aromatic hydrocarbons, while additional eight hydroxylated polycyclic aromatic hydrocarbon masses were screened for using the suspect screening. The target screening was validated with respect to linearity, limits of detection and quantification and matrix effects. The calibration curves ranged from 0.01 to 10 ng/mL, the method limits of detection and. quantification were in the rage of 0.001-0.018 pg/m(3) and 0.006-0.061 pg/m(3), respectively, while matrix effects ranged from 83% to 104%. For the suspect screening, a list with expected precursor ions created from suspect monoisotopic masses was used. The suspects were then identified by the accurate exact mass, with a mass accuracy threshold < 5 ppm, molecular formula, isotopic pattern, and mass spectra (fragments) and also semi-quantified in order to obtain information on their relative levels in different matrixes. The developed strategy was applied on five air particulate samples collected from an urban background and five samples from a car tunnel in Stockholm (Sweden). In total 20 hydroxylated polycyclic aromatic hydrocarbons were detected, of which nine compounds were determined using the target screening and 11 were tentatively identified and semi-quantified using the suspect screening strategy. The concentrations of the target compounds ranged from 20.7 to 96.9 pg/m(3), for most of the analytes the concentrations in particles from car tunnel were slightly higher than in urban air particles. The levels of most of the tentatively identified compounds were also slightly higher in particles from the car tunnel.

  • 13.
    Avagyan, Rozanna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Åberg, Magnus
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Suspect screening of OH-PAHs and non-target screening of other organic compounds in wood smoke particles using HR-Orbitrap-MS2016In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 163, p. 313-321Article in journal (Refereed)
    Abstract [en]

    Wood combustion has been shown to contribute significantly to emissions of polycyclic aromatic hydrocarbons and hydroxylated polycyclic aromatic hydrocarbons, compounds with toxic and carcinogenic properties. However, only a small number of hydroxylated polycyclic aromatic hydrocarbons have been determined in particles from wood combustion, usually compounds with available reference standards. In this present study, suspect and non-target screening strategies were applied to characterize the wood smoke particles from four different wood types and two combustion conditions with respect to hydroxylated polycyclic aromatic hydrocarbons and other organic compounds. In the suspect screening, 32 peaks corresponding to 12 monohydroxylated masses were tentatively identified by elemental composition assignments and matching of isotopic pattern and fragments. More than one structure was suggested for most of the measured masses. Statistical analysis was performed on the non-target screening data in order to single out significant peaks having intensities that depend on the wood type and/or combustion condition. Significant peaks were found in both negative and positive ionization modes, with unique peaks for each wood type and combustion condition, as well as a combination of both factors. Furthermore, structural elucidation of some peaks was done by comparing the spectra in the samples with spectra found in the spectral databases. Six compounds were tentatively identified in positive ionization mode, and 19 in negative ionization mode. The results in this present study demonstrate that there are significant overall differences in the chemistry of wood smoke particles that depends on both the wood type and the combustion condition used.

  • 14. Barath, Stefan
    et al.
    Mills, Nicholas L.
    Lundbäck, Magnus
    Törnqvist, Håkan
    Lucking, Andrew J.
    Langrish, Jeremy P.
    Söderberg, Stefan
    Boman, Christoffer
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Londahl, Jakob
    Donaldson, Ken
    Mudway, Ian S.
    Sandström, Thomas
    Newby, David E.
    Blomberg, Anders
    Impaired vascular function after exposure to diesel exhaust generated at urban transient running conditions2010In: Particle and fibre toxicology, ISSN 1743-8977, Vol. 7, p. 19-Article in journal (Refereed)
    Abstract [en]

    Background: Traffic emissions including diesel engine exhaust are associated with increased respiratory and cardiovascular morbidity and mortality. Controlled human exposure studies have demonstrated impaired vascular function after inhalation of exhaust generated by a diesel engine under idling conditions. Objectives: To assess the vascular and fibrinolytic effects of exposure to diesel exhaust generated during urban-cycle running conditions that mimic ambient 'real-world' exposures. Methods: In a randomised double-blind crossover study, eighteen healthy male volunteers were exposed to diesel exhaust (approximately 250 mu g/m(3)) or filtered air for one hour during intermittent exercise. Diesel exhaust was generated during the urban part of the standardized European Transient Cycle. Six hours post-exposure, vascular vasomotor and fibrinolytic function was assessed during venous occlusion plethysmography with intra-arterial agonist infusions. Measurements and Main Results: Forearm blood flow increased in a dose-dependent manner with both endothelial-dependent (acetylcholine and bradykinin) and endothelial-independent (sodium nitroprusside and verapamil) vasodilators. Diesel exhaust exposure attenuated the vasodilatation to acetylcholine (P < 0.001), bradykinin (P < 0.05), sodium nitroprusside (P < 0.05) and verapamil (P < 0.001). In addition, the net release of tissue plasminogen activator during bradykinin infusion was impaired following diesel exhaust exposure (P < 0.05). Conclusion: Exposure to diesel exhaust generated under transient running conditions, as a relevant model of urban air pollution, impairs vasomotor function and endogenous fibrinolysis in a similar way as exposure to diesel exhaust generated at idling. This indicates that adverse vascular effects of diesel exhaust inhalation occur over different running conditions with varying exhaust composition and concentrations as well as physicochemical particle properties. Importantly, exposure to diesel exhaust under ETC conditions was also associated with a novel finding of impaired of calcium channel-dependent vasomotor function. This implies that certain cardiovascular endpoints seem to be related to general diesel exhaust properties, whereas the novel calcium flux-related effect may be associated with exhaust properties more specific for the ETC condition, for example a higher content of diesel soot particles along with their adsorbed organic compounds.

  • 15. Batistuzzo, S.
    et al.
    Galvão, M. O.
    Duarte, E. S.
    Hoelzemann, J. J.
    Menezes Filho, J.
    Sadiktsis, Ioannis
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Dreij, K.
    PAH exposure and relationship between buccal micronucleus cytome assay and urinary 1-hydroxypyrene levels among cashew nut roasting workers2016In: Toxicology Letters, ISSN 0378-4274, E-ISSN 1879-3169, Vol. 258, p. S223-S224Article in journal (Refereed)
    Abstract [en]

    The present study conducted the first assessment of the occupational risk associated to artisanal cashew nut roasting by the use of exposure and effect biomarkers, as well as the characterization and dispersion analysis of the released particulate matter (PM). The PM concentrations in the exposed area were higher than in the non-exposed area. Furthermore, in the control area yielded a higher prevalence of coarse particles, while in the exposed area was observed fine particles. The morphological analysis showed a wide variety of particles. Biomass burning tracers K, Cl, S and Ca were the major inorganic compounds and polycyclic aromatic hydrocarbons (PAHs) with mutagenic and carcinogenic potential, such as benzo[a]pyrene, benzo[b]fluoranthene, benzo[a]anthracene, benzo[j]fluoranthene and indeno[1,2,3-c,d]pyrene were the most abundant PAHs. In addition, atmospheric modeling analysis suggest that these particles can reach regions higher than 40 kilometers. Occupational PAH exposure was confirmed by increases in 1-OHP levels in cashew nut workers. The frequencies of BMCyt biomarkers of genotoxic (micronuclei and nuclear bud) and cytotoxic (pyknosis, karyolysis, karyorrhexis and condensed chromatin) were higher in the exposed group (p < 0.0001) compared with the control group. The influence of factors such as age on the micronucleus was evidenced and a correlation between 1-OHP and MN was observed. It was the first study to found a correlation between these types of biomarkers. The uses of exposure and effect biomarkers were therefore efficient in assessing the occupational risk associated with artisanal cashew nut roasting and the high rates of PM2.5 are considered a potential contributor to this effect.

  • 16.
    Bergvall, C
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Westerholm, R
    Accelerated Solvent Extraction for Determination of Benzo(a)pyrene in Diesel Particulate Matter2007In: NOSA Aerosol Symposium, 2007Conference paper (Other (popular science, discussion, etc.))
  • 17.
    Bergvall, C
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Westerholm, R
    Evaluation of Accelerated Solvent Extraction of deuterated benzo(a)pyrene and dibenzo(a,i)pyrene from Diesel Standard Reference Material 29752007In: ISPAC 2007, 2007Conference paper (Other (popular science, discussion, etc.))
  • 18.
    Bergvall, Christoffer
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Determination of 252-302 Da and tentative identification of 316-376 Da polycyclic aromatic hydrocarbons in Standard Reference Materials 1649a Urban Dust and 1650b and 2975 Diesel Particulate Matter by accelerated solvent extraction-HPLC-GC-MS.2008In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 391, no 6, p. 2235-2248Article in journal (Refereed)
    Abstract [en]

    We have assessed and compared the extraction recoveries of polycyclic aromatic hydrocarbons (PAHs) with molecular weights of 252, 276, 278, 300 and 302 from diesel particulate matter (PM) and urban air particles using ultrasonically-assisted extraction and accelerated solvent extraction methods, and evaluated the effects of sample and treatment parameters. The results show that accelerated solvent extraction can extract PAHs more efficiently from diesel PM than ultrasonically assisted extraction. They also show that PAHs are more difficult to extract from diesel PM than from urban air particles. Using toluene and maximum instrumental settings (200 ºC, 3000 psi and five extraction cycles) with 30 min static extraction times > 85 % of the analytes were estimated to be extracted from the diesel particles, but four extraction cycles with just 5 min static extraction times under these conditions seems to be sufficient to extract > 95 % of the analytes from the urban air particles. The accelerated solvent extraction method was validated using Standard Reference Materials (SRM) 1649a, Urban Dust, SRM 2975 and SRM 1650a, Diesel Particulate Matter, from the US National Institute of Standards and Technology (NIST). PAH concentrations determined by on-line high performance liquid chromatography-gas chromatography-mass spectrometry following the developed accelerated solvent extraction method were generally higher than the certified and reference NIST values and concentrations reported in the literature (e.g. the estimated concentration of benzo(a)pyrene in SRM 2975 was 15-fold higher than the NIST-certified value), probably because the extraction recoveries were higher than in previous studies. The developed accelerated solvent extraction method was used to analyze high molecular weight PAHs (Mw>302) in the investigated SRMs, and more than 170 (SRM 1649a), 80 (SRM 1650b) and 60 (SRM 2975) potential high molecular weight PAHs were tentatively identified in them, with molecular weights (depending on the SRM sample analysed) of 316, 326, 328, 340, 342, 350, 352, 366, 374 and 376. This is, to our knowledge, the first study to tentatively report PAHs with molecular weights of 316, 326, 328, 342, 350, 352, 366 and 374 in diesel particulate matter. GC-MS chromatograms obtained in selected ion monitoring mode (extracted ions for the above mentioned m/z) and full-scan mass spectra of tentatively identified high molecular weight PAHs are shown in the electronical supplementary material.

  • 19.
    Bergvall, Christoffer
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Westerholm, Roger
    Identification and Determination of Highly Carcinogenic Dibenzopyrene Isomers in Air Particulate Samples from a Street Canyon, a Rooftop, and a Subway Station in Stockholm2007In: Environmental Science & Technology, ISSN 0013-936X, Vol. 41, no 3, p. 731-737Article in journal (Refereed)
    Abstract [en]

    This study presents determined levels of the highly carcinogenic dibenzopyrene isomers dibenzo(a,l)pyrene, dibenzo(a,e)pyrene, dibenzo(a,i)pyrene, and dibenzo(a,h)pyrene as well as three other polycyclic aromatic hydrocarbons (PAHs)benzo(a)pyrene, perylene and coronenein ambient particulate material samples from a street canyon, a rooftop, and an underground subway station in Stockholm, Sweden. To our knowledge, these are the first reported determinations of dibenzopyrene isomers in air particles from either Stockholm or a subway station. Taking into account both concentration and toxic equivalence factors (TEFs), the PAH with the highest carcinogenic potency in the analyzed samples was dibenzo(a,l)pyrene, and the sum carcinogenic potency of the determined dibenzopyrenes was about 1−4 times higher than that of benzo(a)pyrene in the analyzed samples. These findings indicate that it is important to analyze the dibenzopyrene isomers as well as benzo(a)pyrene; the common approach of using benzo(a)pyrene as an indicator substance could lead to underestimates of the potential carcinogenic potency of PAHs in ambient air. The results also indicate that the relative carcinogenic potency of the determined dibenzopyrenes and benzo(a)pyrene in air particles from Stockholm is similar to that of air particles sampled in Washington in 1976−1977, despite general improvements in air quality in the intervening period. However, more data are needed to characterize temporal variations in dibenzopyrene levels in locations such as subway stations, suburbs, road tunnels, and metropolitan areas. There is also a need to identify and characterize both stationary and mobile PAH sources with respect to emission of dibenzopyrene isomers.

  • 20.
    Bergvall, Christoffer
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Polycyclic Aromatic Hydrocarbons (PAHs) with molecular weights > 252 u in particulate matter originating from a domestic heating system fuelled with wheat2009Conference paper (Other academic)
    Abstract [en]

    Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous environmental pollutants formed during the incomplete combustion of organic matter in air. PAHs with molecular weights (Mw) < 302 u have previously been determined in particulate matter originating from combustion of wheat. However, no studies exist in the literature on determination of high molecular weight (HMW) PAHs i.e. with Mw ≥ 302 u in particulate matter from wheat combustion. The particulate matter used in the present study was sampled from the exhausts generated from a 20 kW multi fuel boiler designed for the use of various bio-fuels such as cereals, wood pellets and wood chips (Baxi combi heath 2.5, Baxi, Sweden). The particulate matter was analyzed using the same method that previously has been used by our group to detect HMW PAHs in urban air particulate matter and diesel particulates. The particulate matter was extracted with toluene using Accelerated Solvent Extraction (ASE), cleaned up using silica solid phase extraction (SPE) cartridges and analyzed using on-line hyphenated High Performance Liquid Chromatography (HPLC)-Gas Chromatography (GC)-Mass Spectrometry (MS).This study presents for the first time quantitative data of the dibenzopyrene isomers (Mw 302 u) dibenzo(a,l)pyrene, dibenzo(a,e)pyrene, dibenzo(a,i)pyrene and dibenzo(a,h)pyrene as well as full scan mass spectra of tentatively identified HMW PAHs with Mw of 314 u, 316 u, 324 u, 326 u, 328 u, 340 u, 350 u, 352 u and 374 u detected in particulate matter from domestic heating using wheat as fuel. Comparisons are made with a recent publication in which we presented full scan mass spectra of HMW PAHs detected in the Standard Reference Materials (SRMs) 1649a Urban Dust and 1650b and 2975 Diesel Particulate Matter obtained from the National Institute of Standards and Technology (NIST). The mean amount of PAHs (Mw 252 u-302 u) found in the wheat combustion generated particulate matter was approximately a factor 3 and 6 times higher than what we have previously found in particulate matter originating from modern and older diesel engines, respectively. Björn Holstensson is acknowledged for providing the multi fuel boiler. Stefan Gustavsson and Lena Elfver are acknowledged for skillful sampling and laboratory work. The research project is financed by Stockholm University and Härseby farm.

  • 21. Boman, C
    et al.
    Forsberg, B
    Sandström, T
    Sehlstdt, M
    Westerholm, R
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    The Role of Particle Size and Chemical Composition for Health Effects-A Review of the Current Literature. Report to Swedish Emission Research Project (EMFO)2007Report (Other academic)
  • 22. Boman, Christoffer
    et al.
    Pettersson, Esbjorn
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Bostrom, Dan
    Nordin, Anders
    Stove Performance and Emission Characteristics in Residential Wood Log and Pellet Combustion, Part 1: Pellet Stoves2011In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 25, p. 307-314Article in journal (Refereed)
    Abstract [en]

    Stove performance, characteristics, and quantities of gaseous and particulate emissions were determined for two different pellet stoves, varying fuel load, pellet diameter, and chimney draft. This approach aimed at covering variations in emissions from stoves in use today. The extensive measurement campaign included CO, NO(x), organic gaseous carbon, volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), total particulate matter (PM(tot)) as well as particle mass and number concentrations, size distributions, and inorganic composition. At high load, most emissions were similar. For stove B, operating at high residual oxygen and solely with primary air, the emissions of PM,, and particle numbers were higher while the particles were smaller. Lowering the fuel load, the emissions of CO and hydrocarbons increased dramatically for stove A, which operated continuously also at lower fuel loads. On the other hand for stove B, which had intermittent operation at lower fuel loads, the emissions of hydrocarbons increased only slightly lowering the fuel load, while CO emissions increased sharply, due to high emissions at the end of the combustion cycle. Beside methane, dominating VOCs were ethene, acetylene, and benzene and the emissions of VOC varied in the range 1.1-42 mg/MJ(fuel). PAH emissions (2-340 mu g/MJ(fuel)) were generally dominated by phenanthrene, fluoranthene and pyrene. The PM(tot) values (15-45 mg/MJ(fuel)) were in all cases dominated by fine particles with mass median diameters in the range 100-200 nm, peak mobility diameters of 50-85 nm, and number concentrations in the range 4 x 10(13) to 3 x 10(14) particles/MJ(fuel). During high load conditions, the particulate matter was totally dominated by inorganic particles at 15-25 mg/MJ(fuel) consisting of potassium, sodium, sulfur, and chlorine, in the form of K(2)SO(4), K(3)Na(SO(4))(2), and KCl. The study shows that differences in operation and modulation principles for the tested pellet stoves, relevant for appliances in use today, will affect the performance and emissions significantly, although with lower scattering in the present study compared to compiled literature data.

  • 23. Dreij, Kristian
    et al.
    Mattsson, Åse
    Jarvis, Ian W. H.
    Lim, Hwanmi
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Hurkmans, Jennie
    Gustafsson, Johan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Johansson, Christer
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Environment and Health Administration, Sweden.
    Stenius, Ulla
    Cancer Risk Assessment of Airborne PAHs Based on in Vitro Mixture Potency Factors2017In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 51, no 15, p. 8805-8814Article in journal (Refereed)
    Abstract [en]

    Complex mixtures of polycyclic aromatic hydrocarbons (PAHs) are common environmental pollutants associated with adverse human health effects including cancer. However, the risk of exposure to mixtures is difficult to estimate, and risk assessment by whole mixture potency evaluations has been suggested. To facilitate this, reliable in vitro based testing systems are necessary. Here, we investigated if activation of DNA damage signaling in vitro could be an endpoint for developing whole mixture potency factors (MPFs) for airborne PAHs. Activation of DNA damage signaling was assessed by phosphorylation of Chid and H2AX using Western blotting. To validate the in vitro approach, potency factors were determined for seven individual PAHs which were in very good agreement with established potency factors based on cancer data in vivo. Applying the method using Stockholm air PAH samples indicated MPFs with orders of magnitude higher carcinogenic potency than predicted by established in vivo-based potency factors. Applying the MPFs in cancer risk assessment suggested that 45.4 (6% of all) cancer cases per year in Stockholm are due to airborne PAHs. Applying established models resulted in <1 cancer case per year, which is far from expected levels. We conclude that our in vitro based approach for establishing MPFs could be a novel method to assess whole mixture samples of airborne PAHs to improve health risk assessment.

  • 24. Eriksson, A. C.
    et al.
    Nordin, E. Z.
    Nyström, R.
    Pettersson, E.
    Swietlicki, E.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Boman, C.
    Pagels, J. H.
    Particulate PAH Emissions from Residential Biomass Combustion: Time-Resolved Analysis with Aerosol Mass Spectrometry2014In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 48, no 12, p. 7143-7150Article in journal (Refereed)
    Abstract [en]

    Time-resolved emissions of particulate polycyclic aromatic hydrocarbons (PAHs) and total organic particulate matter (OA) from a wood log stove and an adjusted pellet stove were investigated with high-resolution time-of-flight aerosol mass spectrometry (AMS). The highest OA emissions were found during the addition of log wood on glowing embers, that is, slow burning pyrolysis conditions. These emissions contained about 1% PAHs (of OA). The highest PAH emissions were found during fast burning under hot air starved combustion conditions, in both stoves. In the latter case, PAHs contributed up to 40% of OA, likely due to thermal degradation of other condensable species. The distribution of PAHs was also shifted toward larger molecules in these emissions. AMS signals attributed to PAHs were found at molecular weights up to 600 Da. The vacuum aerodynamic size distribution was found to be bimodal with a smaller mode (Dva ~ 200 nm) dominating under hot air starved combustion and a larger sized mode dominating under slow burning pyrolysis (Dva ~ 600 nm). Simultaneous reduction of PAHs, OA and total particulate matter from residential biomass combustion may prove to be a challenge for environmental legislation efforts as these classes of emissions are elevated at different combustion conditions.

  • 25. Hunter, Amanda L
    et al.
    Unosson, Jon
    Bosson, Jenny A
    Langrish, Jeremy P
    Pourazar, Jamshid
    Raftis, Jennifer B
    Miller, Mark R
    Lucking, Andrew J
    Boman, Christoffer
    Nyström, Robin
    Donaldson, Kenneth
    Flapan, Andrew D
    Shah, Anoop SV
    Pung, Louis
    Sadiktsis, Ioannis
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Masala, Silvia
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Sandström, Thomas
    Blomberg, Anders
    Newby, David E
    Mills, Nicholas L
    Effect of wood smoke exposure on vascular function and thrombus formation in healthy fire fighters2014In: Particle and Fibre Toxicology, ISSN 1743-8977, E-ISSN 1743-8977, Vol. 11, no 62Article in journal (Refereed)
    Abstract [en]

    Background

    Myocardial infarction is the leading cause of death in fire fighters and has been linked with exposure to air pollution and fire suppression duties. We therefore investigated the effects of wood smoke exposure on vascular vasomotor and fibrinolytic function, and thrombus formation in healthy fire fighters.

    Methods

    In a double-blind randomized cross-over study, 16 healthy male fire fighters were exposed to wood smoke (~1 mg/m3 particulate matter concentration) or filtered air for one hour during intermittent exercise. Arterial pressure and stiffness were measured before and immediately after exposure, and forearm blood flow was measured during intra-brachial infusion of endothelium-dependent and -independent vasodilators 4–6 hours after exposure. Thrombus formation was assessed using the ex vivo Badimon chamber at 2 hours, and platelet activation was measured using flow cytometry for up to 24 hours after the exposure.

    Results

    Compared to filtered air, exposure to wood smoke increased blood carboxyhaemoglobin concentrations (1.3% versus 0.8%; P < 0.001), but had no effect on arterial pressure,augmentation index or pulse wave velocity (P > 0.05 for all). Whilst there was a dose-dependent increase in forearm blood flow with each vasodilator (P < 0.01 for all), there were no differences in blood flow responses to acetylcholine, sodium nitroprusside or verapamil between exposures (P > 0.05 for all). Following exposure to wood smoke, vasodilatation tobradykinin increased (P = 0.003), but there was no effect on bradykinin-induced tissue-plasminogen activator release, thrombus area or markers of platelet activation (P > 0.05 for all).

    Conclusions

    Wood smoke exposure does not impair vascular vasomotor or fibrinolytic function, or increase thrombus formation in fire fighters. Acute cardiovascular events following firesuppression may be precipitated by exposure to other air pollutants or through other mechanisms, such as strenuous physical exertion and dehydration.

  • 26. Jarvis, Ian W. H.
    et al.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Bottai, Matteo
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Stenius, Ulla
    Dreij, Kristian
    Persistent activation of DNA damage signaling in response to complex mixtures of PAHs in air particulate matter2013In: Toxicology and Applied Pharmacology, ISSN 0041-008X, E-ISSN 1096-0333, Vol. 266, no 3, p. 408-418Article in journal (Refereed)
    Abstract [en]

    Complex mixtures of polycyclic aromatic hydrocarbons (PAHs) are present in air particulate matter (PM) and have been associated with many adverse human health effects including cancer and respiratory disease. However, due to their complexity, the risk of exposure to mixtures is difficult to estimate. In the present study the effects of binary mixtures of benzo[a]pyrene (BP) and dibenzo[a,l]pyrene (DBP) and complex mixtures of PAHs in urban air PM extracts on DNA damage signaling was investigated. Applying a statistical model to the data we observed a more than additive response for binary mixtures of BP and DBP on activation of DNA damage signaling. Persistent activation of checkpoint kinase 1 (Chk1) was observed at significantly lower BP equivalent concentrations in air PM extracts than BP alone. Activation of DNA damage signaling was also more persistent in air PM fractions containing PAHs with more than four aromatic rings suggesting larger PAHs contribute a greater risk to human health. Altogether our data suggests that human health risk assessment based on additivity such as toxicity equivalency factor scales may significantly underestimate the risk of exposure to complex mixtures of PAHs. The data confirms our previous findings with PAH-contaminated soil (Niziolek-Kierecka et al., 2012) and suggests a possible role for Chk1 Ser317 phosphorylation as a biological marker for future analyses of complex mixtures of PAHs.

  • 27. Jarvis, I.W.H.
    et al.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Morales, D.A.
    Kummrow, F.
    Umbuzeiro, G.A.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Dreij, K.
    Nanomolar levels of PAHs in extracts from urban air induce MAPK signaling in HepG2 cells2014In: Toxicology Letters, ISSN 0378-4274, E-ISSN 1879-3169, Vol. 229, no 1, p. 25-32Article in journal (Refereed)
    Abstract [en]

    Polycyclic aromatic hydrocarbons (PAHs) are common environmental pollutants that occur naturally in complex mixtures. Many of the adverse health effects of PAHs including cancer are linked to the activation of intracellular stress response signaling. This study has investigated intracellular MAPK signaling in response to PAHs in extracts from urban air collected in Stockholm, Sweden and Limeira, Brazil, in comparison to BP in HepG2 cells. Nanomolar concentrations of PAHs in the extracts induced activation of MEK4 signaling with down-stream increased gene expression of several important stress response mediators. Involvement of the MEK4/JNK pathway was confirmed using siRNA and an inhibitor of JNK signaling resulting in significantly reduced MAPK signaling transactivated by the AP-1 transcription factors ATF2 and c-Jun. ATF2 was also identified as a sensitive stress responsive protein with activation observed at extract concentrations equivalent to 0.1 nM BP. We show that exposure to low levels of environmental PAH mixtures more strongly activates these signaling pathways compared to BP alone suggesting effects due to interactions. Taken together, this is the first study showing the involvement of MEK4/JNK/AP-1 pathway in regulating the intracellular stress response after exposure to nanomolar levels of PAHs in environmental mixtures.

  • 28. Kocbach Bølling, Anette
    et al.
    Totlandsdal, Annike Irene
    Sallsten, Gerd
    Braun, Artur
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Boman, Johan
    Dahlman, Hans Jørgen
    Sehlstedt, Maria
    Herseth, Jan Inge
    Wood smoke particles from different combustion phases induce similar pro-inflammatory effects in a co-culture of monocyte and pneumocyte cell lines2012In: Particle and Fibre Toxicology, ISSN 1743-8977, E-ISSN 1743-8977, Vol. 9, p. 45-Article in journal (Refereed)
    Abstract [en]

    Background: Exposure to particulate matter (PM) has been linked to several adverse cardiopulmonary effects, probably via biological mechanisms involving inflammation. The pro-inflammatory potential of PM depends on the particles' physical and chemical characteristics, which again depend on the emitting source. Wood combustion is a major source of ambient air pollution in Northern countries during the winter season. The overall aim of this study was therefore to investigate cellular responses to wood smoke particles (WSPs) collected from different phases of the combustion cycle, and from combustion at different temperatures. Results: WSPs from different phases of the combustion cycle induced very similar effects on pro-inflammatory mediator release, cytotoxicity and cell number, whereas WSPs from medium-temperature combustion were more cytotoxic than WSPs from high-temperature incomplete combustion. Furthermore, comparisons of effects induced by native WSPs with the corresponding organic extracts and washed particles revealed that the organic fraction was the most important determinant for the WSP-induced effects. However, the responses induced by the organic fraction could generally not be linked to the content of the measured polycyclic aromatic hydrocarbons (PAHs), suggesting that also other organic compounds were involved. Conclusion: The toxicity of WSPs seems to a large extent to be determined by stove type and combustion conditions, rather than the phase of the combustion cycle. Notably, this toxicity seems to strongly depend on the organic fraction, and it is probably associated with organic components other than the commonly measured unsubstituted PAHs.

  • 29.
    Lim, Hwanmi
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ahmed, Trifa M.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Livsmedelsverket, Sweden.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Uppsala University, Sweden.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Automated clean-up, separation and detection of polycyclic aromatic hydrocarbons in particulate matter extracts using a 2D-LC/2D-GC system: a method translation from two FIDs to two MS detectors2017In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 409, no 24, p. 5619-5629Article in journal (Refereed)
    Abstract [en]

    An online two-dimensional (2D) liquid chromatography/2D gas chromatography system with two mass-selective detectors has been developed on the basis of a previous system with two flame ionization detectors. The method translation involved the change of carrier gas from hydrogen to helium, column dimension and detectors. The 2D system with two mass-selective detectors was validated with use of polycyclic aromatic hydrocarbon (PAH) standards and two standard reference materials from air and diesel exhaust. Furthermore, the system was applied to a real sample, wood smoke particulates. The PAH values determined correlated well with the previous data and those from the National Institute of Standards and Technology. The system enhanced the benefits of the previous system, which were limited by the low detectability and lack of mass selectivity. This study shows an automated 2D system that is valid for PAH analysis of complex environmental samples directly from crude extracts.

  • 30.
    Lim, Hwanmi
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Jarvis, Ian
    Mattsson, Åse
    Dreij, Kristian
    Stenius, Ulla
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Benzo[a]pyrene-specific online high-performance liquid chromatography fractionation of air particulate extracts–A tool for evaluating biological interactions2014In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1355, p. 100-106Article in journal (Refereed)
    Abstract [en]

    Benzo[a]pyrene (B[a]P) is a known human carcinogen and is commonly used as a surrogate for assessing the carcinogenic risk posed by complex mixtures of polycyclic aromatic hydrocarbons (PAHs) present in air particulate matter (PM). However, studies have shown that using B[a]P as a surrogate may underestimate the carcinogenic potential of PAH mixtures, as the risk assessment approach does not consider interaction effects. Thus, toxicological studies using B[a]P to assess its carcinogenic potential in environmentally derived complex mixtures, as opposed to single compound experiments, could improve risk assessment. The intention of the present study was to develop an online HPLC fractionation system for the selective removal of B[a]P from air PM extracts. Two serial pyrenylethyl (PYE) columns enabled selective separation of B[a]P from its isomers and other PAHs as well as a short fractionation cycle of 30 minutes. One run consisted of three collection steps: the first fraction contained PAHs eluting earlier than B[a]P, the second contained B[a]P and the last contained later-eluting PAHs. The selectivity and recovery of the system was investigated using extracts of Stockholm air PM samples. The overall recovery for all PAHs was approximately 80%, and the system proved to be selective, as it removed 94% of B[a]P and less than 3% of benzo[b]fluoranthene from the complex PAH mixture. Exposing human cells to blanks generated by the fractionation system did not induce cytotoxicity or DNA damage signalling. In conclusion, the online HPLC system was selective for B[a]P fractionation whilst minimising run-to-run variation and allowing repeated fractionations for larger samples due to its relatively short run time

  • 31.
    Lim, Hwanmi
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Mattsson, Åse
    Jarvis, Ian W. H.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bottai, Matteo
    Morales, Daniel A.
    Kummrow, Fabio
    Umbuzeiro, Gisela A.
    Stenius, Ulla
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Dreij, Kristian
    Detection of Benz[j]aceanthrylene in Urban Air and Evaluation of Its Genotoxic Potential2015In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 49, no 5, p. 3101-3109Article in journal (Refereed)
    Abstract [en]

    Benz[j]aceanthrylene (B[j]A) is a cyclopenta-fused polycyclic aromatic hydrocarbon with strong mutagenic and carcinogenic effects. We have identified B[j]A in air particulate matter (PM) in samples collected in Stockholm, Sweden and in Limeira, Brazil using LC-GC/MS analysis. Determined concentrations ranged between 1.57 and 12.7 and 19.6-30.2 pg/m(3) in Stockholm and Limeira, respectively, which was 11-30 times less than benzo[a]pyrene (B[a]P) concentrations. Activation of the DNA damage response was evaluated after exposure to B[j]A in HepG2 cells in comparison to B[a]P. We found that significantly lower concentrations of B[j]A were needed for an effect on cell viability compared to B[a]P, and equimolar exposure resulted in significant more DNA damage with B[j]A. Additionally, levels of gamma H2AX, pChk1, p53, pp53, and p21 proteins were higher in response to B[j]A than B[a]P. On the basis of dose response induction of pChk1 and gamma H2AX, B[j]A potency was 12.5- and 33.3-fold higher than B[a]P, respectively. Although B[j]A levels in air were low, including B[j]A in the estimation of excess lifetime cancer risk increased the risk up to 2-fold depending on which potency factor for B[j]A was applied. Together, our results show that B[j]A could be an important contributor to the cancer risk of air PM.

  • 32.
    Masala, Silvia
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Ahmed, Trifa
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Improved efficiency of extraction of polycyclic aromatic hydrocarbons (PAHs) from the National Institute of Standards and Technology (NIST) Standard Reference Material Diesel Particulate Matter (SRM 2975) using accelerated solvent extraction2011In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 401, no 10, p. 3305-3315Article in journal (Refereed)
    Abstract [en]

    The efficiency of extraction of polycyclic aromatic hydrocarbons (PAHs) with molecular masses of 252, 276, 278, 300, and 302 Da from standard reference material diesel particulate matter (SRM 2975) has been investigated using accelerated solvent extraction (ASE) with dichloromethane, toluene, methanol, and mixtures of toluene and methanol. Extraction of SRM 2975 using toluene/methanol (9:1, v/v) at maximum instrumental settings (200 A degrees C, 20.7 MPa, and five extraction cycles) with 30-min extraction times resulted in the following elevations of the measured concentration when compared with the certified and reference concentrations reported by the National Institute of Standards and Technology (NIST): benzo[b]fluoranthene, 46%; benzo[k]fluoranthene, 137%; benzo[e]pyrene, 103%; benzo[a]pyrene, 1,570%; perylene, 37%; indeno[1,2,3-cd]pyrene, 41%; benzo[ghi]perylene, 163%; and coronene, 361%. The concentrations of the following PAHs were comparable to the reference values assigned by NIST: indeno[1,2,3-cd]fluoranthene, dibenz[a,h]anthracene, and picene. The measured concentration of dibenzo[a,e]-pyrene was lower than the information value reported by the NIST. The measured concentrations of other highly carcinogenic PAHs (dibenzo[a,l]pyrene, dibenzo[a,i]pyrene, and dibenzo[a,h]pyrene) in SRM 2975 are also reported. Comparison of measurements using the optimized ASE method and using similar conditions to those applied by the NIST for the assignment of PAH concentrations in SRM 2975 indicated that the higher values obtained in the present study were associated with more complete extraction of PAHs from the diesel particulate material. Re-extraction of the particulate samples demonstrated that the deuterated internal standards were more readily recovered than the native PAHs, which may explain the lower values reported by the NIST. The analytical results obtained in the study demonstrated that the efficient extraction of PAHs from SRM 2975 is a critical requirement for the accurate determination of PAHs with high molecular masses in this standard reference material and that the optimization of extraction conditions is essential to avoid underestimation of the PAH concentrations. The requirement is especially relevant to the human carcinogen benzo[a]pyrene, which is commonly used as an indicator of the carcinogenic risk presented by PAH mixtures.

  • 33.
    Masala, Silvia
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Determination of benzo(a)pyrene and dibenzopyrenes in a Chinese coal fly ash Certified Reference Material2012In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 432, p. 97-102Article in journal (Other academic)
    Abstract [en]

    Air pollution from coal combustion is of great concern in China because coal is the country's principal source of energy and it has been estimated that coal combustion is one of the main sources of polycyclic aromatic hydrocarbon (PAH) emissions in the nation. This study reports the concentrations of 15 PAHs including benzo[a]pyrene, dibenzo[a,l]pyrene, dibenzo[a,e]pyrene, dibenzo[a,i]pyrene and dibenzo[a,h]pyrene in a coal fly ash certified reference material (CRM) from China. To the best of our knowledge, dibenzo[a,l]pyrene, dibenzo[a,i]pyrene and dibenzo[a,h]pyrene concentrations in coal fly ash particles have not previously been reported. Benzo[a]pyrene is the only one of the studied hydrocarbons whose concentration in the coal fly ash CRM had previously been certified. The concentration of this species measured in this present work was twice the certified value. This is probably because of the exhaustive accelerated solvent extraction method employed. Consecutive extractions indicated an extraction recovery in excess of 95% for benzo[a]pyrene. For the other determined PAHs, repeat extractions indicated recoveries above 90%.

  • 34.
    Masala, Silvia
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Lim, Hwanmi
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Johansson, Christer
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Environment and Health Administration, Sweden.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Determination of semi-volatile and particle-associated polycyclic aromatic hydrocarbons in Stockholm air with emphasis on the highly carcinogenic dibenzopyrene isomers2016In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 140, p. 370-380Article in journal (Refereed)
    Abstract [en]

    The concentrations of polycyclic aromatic hydrocarbons (PAHs) have been determined in the gaseous phase and in various particulate matter (PM) size fractions at different locations in and outside of Stockholm, Sweden, representative of street level, urban and rural background. The focus has been on the seldom determined but highly carcinogenic dibenzopyrene isomers (DBPs) dibenzo[a,I]pyrene, dibenzo [a,e]pyrene, dibenzo[a,i]pyrene and dibenzo[a,h]pyrene. PAHs with 3 rings were found to be mainly associated with the vapor phase (>90%) whereas PAHs with 5-6 rings were mostly associated with particulate matter (>92%) and the 4-ringed PAHs partitioned between the two phases. PAH abundance was determined to be in the order street level > urban background > rural background with the PM10 street level 2010 mean of benzo[a]pyrene (B[a]P) reaching 0.24 ng/m(3), well below the EU annual limit value of 1 ng/m(3). In addition, higher PAH concentrations were found in the sub-micron particle fraction (PM1) as compared to the super -micron fraction (PM1-10) with the abundance in PM1 varying between 57 and 86% of the total PAHs. The B[a]P equivalent concentrations derived for DB[a,l]P and total DBPs exceeded 1-2 and 2-4 times, respectively, that of B[a]P at the four sampling sites; therefore underestimation of the cancer risk posed by PAHs in air could be made if the DBPs were not considered in risk assessment using the toxic equivalency approach, whilst the high correlation (p < 0.001) found in the relative concentrations supports the use of B[a]P as a marker substance for assessment of the carcinogenic risk associated to PAHs. However, the big difference in concentration ratios of B[a]P and the DBPs between the present study and some literature data calls for further research to evaluate the temporal and spatial invariance of the B[a]P/DBP ratios.

  • 35.
    Masala, Silvia
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Rannug, Ulf
    Stockholm University, Faculty of Science, Department of Genetics, Microbiology and Toxicology.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Pressurized liquid extraction as an alternative to the Soxhlet extraction procedure stated in the US EPA method TO-13A for the recovery of polycyclic aromatic hydrocarbons adsorbed on polyurethane foam plugs2014In: Analytical Methods, ISSN 1759-9660, E-ISSN 1759-9679, Vol. 6, no 20, p. 8420-8425Article in journal (Refereed)
    Abstract [en]

    The aim of the present study was to develop a pressurized liquid extraction (PLE) method as an alternative to the relatively time consuming Soxhlet extraction procedure described in the United States Environmental Protection Agency (US EPA) method TO-13A for the extraction of PAHs adsorbed onto polyurethane foam plugs (PUFs). For this purpose PUF air samples were collected and split into two parts: one part extracted using PLE and the other one using Soxhlet extraction. Comparable PAH concentrations were obtained upon analysis of the extracts showing that the PLE method developed in this work is a more convenient choice than the commonly used Soxhlet extraction technique proposed by US EPA for the determination of PAHs in air samples. In fact, the developed PLE method required shorter assay times (minutes versus hours), less solvent consumption and simpler operational methods. The exhaustiveness of the developed PLE method was evaluated using repeat static extraction cycles, demonstrating an extraction efficiency for the PAHs of greater than 99%. The PLE method was then applied to diesel exhaust and wood smoke PUF samples showing an extraction efficiency for the PAHs of greater than 93% and 96%, respectively. Furthermore, a PLE method for PUF cleaning was developed as well and employed as an alternative to Soxhlet extraction. The PLE methods developed for cleaning and extracting PUFs presented in this work are suitable to be used in mutagenicity studies using the Ames Salmonella assay as no mutagenicity was found in the PLE generated blanks

  • 36.
    Mashayekhy Rad, Farshid
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Spinicci, Silvia
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Silvergren, Sanna
    Nilsson, Ulrika
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Validation of a HILIC/ESI-MS/MS method for the wood burning marker levoglucosan and its isomers in airborne particulate matter2018In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 211, p. 617-623Article in journal (Refereed)
    Abstract [en]

    In the present study, a methodology involving hydrophilic interaction liquid chromatography (HILIC) and electrospray (ESI) tandem mass spectrometry (MS/MS) was developed for measurement of anhydrous monosaccharides as markers for wood burning in atmospheric aerosols, PM10. No extensive sample preparation, other than ultrasound-assisted solvent extraction and evaporation, was applied. A pentahydroxysilica column enabled separation of levoglucosan from mannosan and galactosan within 5 min and the quantitative performance was validated using the standard reference materials (SRM) 1649a and 1649b. The experimentally obtained results for SRMs were in agreement with values previously reported in other studies. Achieved instrumental limits of detection (LODs) were below 10 pg injected on column, corresponding to LODs in air lower than 0.10 ng/m3 for all measured isomers for 2–3 day sampling with 1.0 m−3 h−1 sampling rate.

    The validated method was used for the determination of levoglucosan and its isomers in atmospheric aerosols collected in three different Swedish urban areas during the winter and summer time in 2017. The total measured concentrations for levoglucosan and galactosan + mannosan were determined to be between 78 and 167 ng/m3 in January 2017, which is approximately 10-times higher compared to the levels detected in July, reflecting the higher frequency of wood burning for heating during the cold season. Calculated concentration ratios between levoglucosan and its isomers in the urban area samples indicated mostly mixed softwood/hardwood combustion in winter time; on the other hand, softwood burning was observed as the major emission in summer time.

  • 37. Muala, Ala
    et al.
    Rankin, Gregory
    Sehlstedt, Maria
    Unosson, Jon
    Bosson, Jenny A.
    Behndig, Annelie
    Pourazar, Jamshid
    Nyström, Robin
    Pettersson, Esbjörn
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Jalava, Pasi I.
    Happo, Mikko S.
    Uski, Oskari
    Hirvonen, Maija-Riitta
    Kelly, Frank J.
    Mudway, Ian S.
    Blomberg, Anders
    Boman, Christoffer
    Sandström, Thomas
    Acute exposure to wood smoke from incomplete combustion - indications of cytotoxicity2015In: Particle and Fibre Toxicology, ISSN 1743-8977, E-ISSN 1743-8977, Vol. 12, article id 33Article in journal (Refereed)
    Abstract [en]

    Background: Smoke from combustion of biomass fuels is a major risk factor for respiratory disease, but the underlying mechanisms are poorly understood. The aim of this study was to determine whether exposure to wood smoke from incomplete combustion would elicit airway inflammation in humans. Methods: Fourteen healthy subjects underwent controlled exposures on two separate occasions to filtered air and wood smoke from incomplete combustion with PM1 concentration at 314 mu g/m(3) for 3 h in a chamber. Bronchoscopy with bronchial wash (BW), bronchoalveolar lavage (BAL) and endobronchial mucosal biopsies was performed after 24 h. Differential cell counts and soluble components were analyzed, with biopsies stained for inflammatory markers using immunohistochemistry. In parallel experiments, the toxicity of the particulate matter (PM) generated during the chamber exposures was investigated in vitro using the RAW264.7 macrophage cell line. Results: Significant reductions in macrophage, neutrophil and lymphocyte numbers were observed in BW (p < 0.01, < 0.05, < 0.05, respectively) following the wood smoke exposure, with a reduction in lymphocytes numbers in BAL fluid (< 0.01. This unexpected cellular response was accompanied by decreased levels of sICAM-1, MPO and MMP-9 (p < 0.05, < 0.05 and < 0.01). In contrast, significant increases in submucosal and epithelial CD3+ cells, epithelial CD8+ cells and submucosal mast cells (p < 0.01, < 0.05, < 0.05 and < 0.05, respectively), were observed after wood smoke exposure. The in vitro data demonstrated that wood smoke particles generated under these incomplete combustion conditions induced cell death and DNA damage, with only minor inflammatory responses. Conclusions: Short-term exposure to sooty PAH rich wood smoke did not induce an acute neutrophilic inflammation, a classic hallmark of air pollution exposure in humans. While minor proinflammatory lymphocytic and mast cells effects were observed in the bronchial biopsies, significant reductions in BW and BAL cells and soluble components were noted. This unexpected observation, combined with the in vitro data, suggests that wood smoke particles from incomplete combustion could be potentially cytotoxic. Additional research is required to establish the mechanism of this dramatic reduction in airway leukocytes and to clarify how this acute response contributes to the adverse health effects attributed to wood smoke exposure.

  • 38. Nordin, Erik Z.
    et al.
    Uski, Oskari
    Nyström, Robin
    Jalava, Pasi
    Eriksson, Axel C.
    Genberg, Johan
    Roldin, Pontus
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Jokiniemi, Jorma
    Pagels, Joakim H.
    Boman, Christoffer
    Hirvonen, Maija-Riitta
    Influence of ozone initiated processing on the toxicity of aerosol particles from small scale wood combustion2015In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 102, p. 282-289Article in journal (Refereed)
    Abstract [en]

    Black carbon containing emissions from biomass combustion are being transformed in the atmosphere upon processing induced by tropospheric ozone and UV. The knowledge today is very limited on how atmospheric processing affects the toxicological properties of the emissions. The aim of this study was to investigate the influence of ozone initiated (dark) atmospheric processing on the physicochemical and toxicological properties of particulate emissions from wood combustion. Emissions from a conventional wood stove operated at two combustion conditions (nominal and hot air starved) were diluted and transferred to a chamber. Particulate matter (PM) was collected before and after ozone addition to the chamber using an impactor. Detailed chemical and physical characterization was performed on chamber air and collected PM. The collected PM was investigated toxicologically in vitro with a mouse macrophage model, endpoints included: cell cycle analysis, viability, inflammation and genotoxicity. The results suggest that changes in the organic fraction, including polycyclic aromatic hydrocarbons (PAHs) are the main driver for differences in obtained toxicological effects. Fresh hot air starved emissions containing a higher organic and PAH mass-fraction affected cell viability stronger than fresh emissions from nominal combustion. The PAH mass fractions decreased upon aging due to chemical degradation. Dark aging increased genotoxicity, reduced viability and reduced release of inflammatory markers. These differences were statistically significant for single doses and typically less pronounced. We hypothesize that the alterations in toxicity upon simulated dark aging in the atmosphere may be caused by reaction products that form when PAHs and other organic compounds react with ozone and nitrate radicals. (C) 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/).

  • 39. Nyström, Robin
    et al.
    Lindgren, Robert
    Avagyan, Rozanna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Lundstedt, Staffan
    Boman, Christoffer
    Influence of Wood Species and Burning Conditions on Particle Emission Characteristics in a Residential Wood Stove2017In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 31, no 5, p. 5514-5524Article in journal (Refereed)
    Abstract [en]

    Emissions from small-scale residential biomass combustion are a major source of indoor and outdoor particulate matter (PM) air pollution, and the performance of stoves, boilers, and fireplaces have been shown to be influenced both by fuel properties, technology, and user behavior (firing procedures). Still, rather scarce information is available regarding the relative importance of these variables for the particle characteristics and emissions of different particulate components, e.g., soot, polycyclic aromatic hydrocarbons (PAHs), oxy-PAH, and metals. In particular, the behavior of different wood fuels under varying firing procedures and combustion conditions has not been studied thoroughly. Therefore, the objective of this work was to elucidate the influence of wood species and combustion conditions on particle emission characteristics in a typical Nordic residential wood stove. The emissions from four different wood species were investigated at two controlled combustion conditions, including nominal and high burn rates, with a focus on physical and chemical properties of the fine particulate matter. Considerably elevated carbonaceous particle emissions (soot and organics) were found during high burn rate conditions, which were associated with a shift in particle number size distribution toward a higher fraction of larger particles. In some cases, as here seen for pine, the specific fuel properties can affect the combustion performance and thereby also influence particle and PAH emissions. For the inorganic ash particles, the content in the fuel, and not burning conditions, was found to be the main determining factor, as seen by the increased emissions of alkali salts for aspen. Wood stove emission data on 11 specific oxy-PAHs, together with 45 PAHs, were combined with controlled variations of burning conditions and fuels. The oxy-PAH/PAH ratio during a high burn rate was observed to increase, suggesting an enrichment of particulate oxy-PAH. Accordingly, the main influence on emission performance and particle characteristics was seen between different burn rates, and this study clearly illustrates the major importance of proper operation to avoid unfavorable burning condition, regardless of the wood species used.

  • 40. Nyström, Robin
    et al.
    Sadiktsis, Ioannis
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ahmed, Trifa M.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Koegler, Johannes H.
    Blomberg, Anders
    Sandström, Thomas
    Boman, Christoffer
    Physical and chemical properties of RME biodiesel exhaust particles without engine modifications2016In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 186, p. 102p. 261-269Article in journal (Refereed)
    Abstract [en]

    A major contributor to ambient particulate air pollution is exhaust from diesel engines and other vehicles,which can be linked to different adverse health effects. During the last decades, a global drive towardsfinding sustainable and clean bio-based alternative fuels for the transport sector has taken place and biodieselis one of the most established alternatives today. To better assess the overall effects on a publichealth level when introducing biodiesel and other renewable fuels, a better understanding of the detailedexhaust particle properties, is needed. In this work, the physical and chemical properties of biodieselexhaust particles were studied in comparison to standard diesel exhaust emissions, in an existing enginewithout modifications, focusing on particulate carbonaceous matter and PAH/Oxy-PAH as well as fineparticle size distribution. An older off-road engine, produced between 1996 and 2004, was used withthree different fuels/fuel blends; (1) 100 wt% low-sulfur standard petro diesel (SD), (2) 100 wt% rapeseedmethyl ester biodiesel (B100) and (3) a blended fuel – B30 consisting of 30 wt% RME and 70 wt% SD. Thestudy focused mainly on emissions from transient engine operation, but includes also idling conditions.The gaseous emissions measured for the biodiesel fuel were in general in accordance with previousreported data in the literature, and compared to the standard petro diesel the emissions of CO was lowerwhile NOx emissions increased. The particulate mass concentration during transient operation wasalmost halved compared to when petro diesel was used and this was associated with a decrease in averageparticle size. The shift in particle mass and size was associated with a higher fraction of organic matterin general, considerable less PAH’s but a relative higher fraction of Oxy-PAH’s, when shifting frompetro diesel to biodiesel.

  • 41.
    Olsson, Petter
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Sadiktsis, Ioannis
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Holmbäck, Jan
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Class separation of lipids and polycyclic aromatic hydrocarbons in normal phase high performance liquid chromatography - A prospect for analysis of aromatics in edible vegetable oils and biodiesel exhaust particulates2014In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1360, p. 39-46Article in journal (Refereed)
    Abstract [en]

    The retention characteristics of the major lipid components in biodiesels and edible oils as well as representative polycyclic aromatic compounds (PAHs) have been investigated on five different normal phase HPLC stationary phases, in order to optimize class separation for an automatized online HPLC cleanup of PAHs prior GC-MS analysis. By stepwise comparison of different hexane/MTBE compositions as mobile phases on cyano-, phenyl-, pentabromobenzyl-, nitrophenyl- and amino- modified silica columns, the capacity and selectivity factors for each analyte and column could be calculated. It was concluded that the most suitable column for backflush isolation of PAHs in biodiesel and edible oil matrices was the pentabromobenzyl-modified silica (PBB). A previously described online HPLC-GC-MS system using the PBB column was then evaluated by qualitative and quantitative analysis of a biodiesel exhaust particulate extract and a vegetable oil reference material. The GC-MS full scan analysis of the biodiesel particulate extract showed that the lipids had been removed from the sample and a fraction containing PAHs and oxygenated derivatives thereof had been isolated. Quantified mass fractions of PAHs of the reference material BCR-458 agreed well for most of the certified PAH mass fractions in the spiked coconut oil reference material.

  • 42. Pettersson, Esbjorn
    et al.
    Boman, Christoffer
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Bostrom, Dan
    Nordin, Anders
    Stove Performance and Emission Characteristics in Residential Wood Log and Pellet Combustion, Part 2: Wood Stove2011In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 25, p. 315-323Article in journal (Refereed)
    Abstract [en]

    The characteristics and quantities of a large number of gaseous and particulate emission components during combustion in a residential wood log stove with variations in fuel, appliance and operational conditions were determined experimentally. The measurement campaign included CO, NO(x), organic gaseous carbon (OGC), volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), total particulate matter (PM(tot)) as well as particle mass and number concentrations, size distributions, and inorganic composition. CO varied in the range of 1100 to 7200 mg/MJ(fuel), while OGC varied from 210 to 3300 mg/MJ(fuel). Dominating VOCs were methane, followed by ethene, acetylene, and benzene. Methane varied from 9 to 1600 mg/MJ(fuel). The nonmethane volatile organic compound (NMVOC) emissions were in the range of 20-2300 mg/MJ(fuel). The PAH(tot) emissions varied from 1.3 to 220 mg/MJ(fuel), in most cases dominated by phenantrene, fluoranthene, and pyrene. PM(tot) were in all cases dominated by fine particles and varied in the range 38-350 mg/MJ(fuel). The mass median particle diameters and the peak mobility diameters of the fine particles varied in the range 200-320 and 220-330 nm, respectively, and number concentrations in the range of 1-4 x 10(13) particles/MJ(fuel). Air starved conditions, at high firing intensity, gave the highest emissions, especially for hydrocarbons. This type of condition is seldom considered, though it may occur occasionally. The emissions from Swedish wood stoves, comparing a Swedish field study, are covered fairly well with the applied methodology, but other field studies report considerably higher emissions especially for diluted particle sampling.

  • 43. Pettersson, Esbjörn
    et al.
    Lindmark, Fredrik
    Öhman, Marcus
    Nordin, Anders
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Boman, Christoffer
    Design Changes in a Fixed-Bed Pellet Combustion Device: Effects of Temperature and Residence Time on Emission Performance2010In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 24, no 2, p. 1333-1340Article in journal (Refereed)
    Abstract [en]

    The use of wood fuel pellets has proven to be well-suited for the small-scale market, enabling controlled and efficient combustion with low emission of products of incomplete combustion (PIC). Still! a potential for further emission reduction exists, and it thorough understanding of the influence of combustion Conditions oil the emission characteristics of air pollutants, such as polycyclic aromatic hydrocarbons (PAHs) and particulate matter (PM), is important. The Objective of the present work was to determine the effect of design changes, i.e., increasing the temperature and/or residence time, on the emission performance and characteristics for a pellet combustion device using a laboratory fixed-bed reactor (< 5 kW) The temperature and residence time after the bed Section were varied according to statistical experimental designs (650-950 degrees C and 0.5-3.0 s) with file emission responses: CO, organic gaseous carbon (OGC), NO, volatile organic compounds (VOCs, 20 compounds), PAHs (43 compounds), PMtot mass concentration, fine particle mass/count median diameter (MMD and CMD), and number concentration. The temperature was negatively correlated with the emissions of all studied PIC, with limited effects of the residence time. The PMtot emissions of 15-20 mg/MJ were in all cases dominated by fine (< 1 mu m) particles of K, Na, S, Cl, C, O, and Zn. An increased residence time resulted in increased fine particle sizes (i.e., MMD and CMD) and decreased number concentrations. The Importance of a high temperature (> 850 degrees C in the bed zone with intensive, air-rich, and well-mixed Conditions was illustrated for wood pellets combustion with almost a total depletion Of all Studied PIC. The importance of the residence time was shown to be limited, and file results emphasize the need for further verification studies and technology development work.

  • 44.
    Sadiktsis, Ioannis
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Johansson, Christer
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM). Environment and Health Administration, Stockholm, Sweden.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Automobile Tires-A Potential Source of Highly Carcinogenic Dibenzopyrenes to the Environment2012In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 46, no 6, p. 3326-3334Article in journal (Refereed)
    Abstract [en]

    Eight tires were analyzed for 15 high molecular weight (HMW) polycyclic aromatic hydrocarbons (PAN), using pressurized fluid extraction. The variability of the PAIR concentrations determined between different tires was large; a factor of 22.6 between the lowest and the highest. The relative abundance of the analytes was quite similar regardless of tire. Almost all (92.3%) of the total extractable PAH content was attributed to five PAHs: benzo[ghi]perylene, coronene, indeno[1,2,3-cd]pyrene, benzo[e]pyrene, and benzo[a]pyrene. The difference in the measured PAIR content between summer and winter tires varied substantially across manufacturers, making estimates of total vehicle fleet emissions very uncertain. However, when comparing different types of tires from the same manufacturer they had significantly (p = 0.05) different PAH content. Previously, there have been no data available for carcinogenic dibenzopyrene isomers in automobile tires. In this study, the four dibenzopyrene isomers dibenzo[a,l]pyrene, dibenzo[a,e]pyrene, dibenzo[a,i]pyrene, and dibenzo[a,h]pyrene constituted <2% of the sum of the 15 analyzed HMW PAHs. These findings show that automobile tires may be a potential previously unknown source of carcinogenic dibenzopyrenes to the environment.

  • 45.
    Sadiktsis, Ioannis
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Koegler, Johannes H.
    Benham, Timothy
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Particulate associated polycyclic aromatic hydrocarbon exhaust emissions from a portable power generator fueled with three different fuels – A comparison between petroleum diesel and two biodiesels2014In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 115, p. 573-580Article in journal (Refereed)
    Abstract [en]

    The fuel impact on the emission of more than 40 particulate associated polycyclic aromatic hydrocarbons (PAHs) in the molecular weight range 178–302 Da were investigated. The fuels; neat diesel (EN 590), rape seed methyl ester (B100) and a 30% w/w blend thereof (B30) were tested on a portable power generator without any exhaust aftertreatment. Gaseous emissions of carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NOx) were measured along with particulate emissions and its size distribution for the different fuels. Collected diesel particles were extracted using pressurized fluid extraction and analyzed using an online hyphenated liquid chromatography–gas chromatography–mass spectrometry system.

    The neat B100 and the B30 fuel produced less CO and total PAHs while the emissions of NOx and particulate matter increased compared with petroleum diesel fuel per kW h. The reduction of PAH emissions of the alternative diesel fuels were 36% and 70% for B30 and B100 respectively. While the PAH profiles for the neat diesel fuel and B30 were similar, the profile of B100 differed in the sense that the emission contained a higher percentage of PAHs with higher molecular weights. The emission of these PAHs was however larger using the neat diesel fuel with the exception for some of these higher molecular weight PAHs of which there was an increased emission using B100. Thermogravimetric analysis revealed that the collected particles from B100 contained a substantial amount of volatile components. A mass spectrometric full scan analysis suggests that these volatile components are in fact unburned or partially-burned fuel constituents.

    It is concluded that the particles originating from biodiesel combustion might be very different from those originating from petroleum diesel combustion which places new demands on the development of measurement methodologies originally developed for particulate emissions from petroleum-based fuels.

  • 46.
    Sadiktsis, Ioannis
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Nilsson, Gertrud
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute. Camfil AB, Research and Development Department, Sweden.
    Johansson, Ulf
    Rannug, Ulf
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Removal of polycyclic aromatic hydrocarbons and genotoxic compounds in urban air using air filter materials for mechanical ventilation in buildings2016In: Science and Technology for the Built Environment, ISSN 2374-474X, Vol. 22, no 3, p. 346-355Article in journal (Refereed)
    Abstract [en]

    Humans spend most of their lives in indoor environments; hence, indoor exposure to air pollution may constitute a large part of the total exposure to air pollution. Polycyclic aromatic hydrocarbons are well known for their mutagenicity and carcinogenicity and are ubiquitous in urban environments as a result of combustion from e.g. vehicular traffic. Polycyclic aromatic hydrocarbons associated to air particulate matter in indoor environments originates from several sources including: cooking and heating, outdoor sources, smoking, candle and incense burning. Infiltration has been suspected to be one major source of indoor polycyclic aromatic hydrocarbons. In this study, four different air filter materials intended for mechanical ventilation were tested for their capability to remove particle bound polycyclic aromatic hydrocarbons and other genotoxic compounds from a real urban aerosol. Particles were sampled at two highly trafficked locations in Stockholm using a sampling system capable of sample particles in parallel, thus allowing sampling of filtered and un-filtered air simultaneously. The sampled particles were extracted and analysed for polycyclic aromatic hydrocarbons and the genotoxicity of the organic extract was determined using Ames mutagenicity tests. Each air filters capability of removing polycyclic aromatic hydrocarbons and reducing genotoxic effects was determined by comparing the filtered and un-filtered air samples. The results showed that all air filter materials had the capability of removing polycyclic aromatic hydrocarbons and reduce genotoxic effects downstream the air filter, and that the magnitude of the reduction was correlated with the standardized particulate collection efficiencies of a 0.4 μm particles for the tested air filter materials. However, the filter with the lowest performance did not significantly reduce direct acting mutagens.

  • 47. Sehlstedt, Maria
    et al.
    Dove, Rosamund
    Boman, Christoffer
    Pagels, Joakim
    Swietlicki, Erik
    Londahl, Jakob
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Bosson, Jenny
    Barath, Stefan
    Behndig, Annelie F.
    Pourazar, Jamshid
    Sandström, Thomas
    Mudway, Ian S.
    Blomberg, Anders
    Antioxidant airway responses following experimental exposure to wood smoke in man2010In: Particle and fibre toxicology, ISSN 1743-8977, Vol. 7, p. 21-Article in journal (Refereed)
    Abstract [en]

    Background: Biomass combustion contributes to the production of ambient particulate matter (PM) in rural environments as well as urban settings, but relatively little is known about the health effects of these emissions. The aim of this study was therefore to characterize airway responses in humans exposed to wood smoke PM under controlled conditions. Nineteen healthy volunteers were exposed to both wood smoke, at a particulate matter (PM2.5) concentration of 224 +/- 22 mu g/m(3), and filtered air for three hours with intermittent exercise. The wood smoke was generated employing an experimental set-up with an adjustable wood pellet boiler system under incomplete combustion. Symptoms, lung function, and exhaled NO were measured over exposures, with bronchoscopy performed 24 h post-exposure for characterisation of airway inflammatory and antioxidant responses in airway lavages. Results: Glutathione (GSH) concentrations were enhanced in bronchoalveolar lavage (BAL) after wood smoke exposure vs. air (p = 0.025), together with an increase in upper airway symptoms. Neither lung function, exhaled NO nor systemic nor airway inflammatory parameters in BAL and bronchial mucosal biopsies were significantly affected. Conclusions: Exposure of healthy subjects to wood smoke, derived from an experimental wood pellet boiler operating under incomplete combustion conditions with PM emissions dominated by organic matter, caused an increase in mucosal symptoms and GSH in the alveolar respiratory tract lining fluids but no acute airway inflammatory responses. We contend that this response reflects a mobilisation of GSH to the air-lung interface, consistent with a protective adaptation to the investigated wood smoke exposure.

  • 48. Umbuzeiro, Gisela A.
    et al.
    Kummrow, Fábio
    Morales, Daniel Alexandre
    Alves, Debora Kristina M.
    Lim, Hwanmi
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Jarvis, Ian W. H.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Stenius, Ulla
    Dreij, Kristian
    Sensitivity of salmonella YG5161 for detecting PAH-associated mutagenicity in air particulate matter2014In: Environmental and Molecular Mutagenesis, ISSN 0893-6692, E-ISSN 1098-2280, Vol. 55, no 6, p. 510-517Article in journal (Refereed)
    Abstract [en]

    The Salmonella/microsome assay is the most used assay for the evaluation of air particulate matter (PM) mutagenicity and a positive correlation between strain TA98 responses and benzo[a]pyrene (B[a]P) levels in PM has been found. However, it seems that the major causes of PM mutagenicity in this assay are the nitro and oxy-PAHs. Salmonella YG5161, a 30-times more responsive strain to B[a]P has been developed. To verify if YG5161 strain was sufficiently sensitive to detect mutagenicity associated with B[a]P mutagenicity, PM samples were collected in Brazil and Sweden, extracted with toluene and tested in the Salmonella/microsome microsuspension assay. PAHs and B[a]P were determined and the extracts were tested with YG5161 and its parental strain TA1538. The extracts were also tested with YG1041 and its parental strain TA98. For sensitivity comparisons, we tested B[a]P and 1-nitropyrene (1-NP) using the same conditions. The minimal effective dose of B[a]P was 155 ng/plate for TA1538 and 7 ng/plate for YG5161. Although the maximum tested dose, 10 m3/plate containing 9 ng of B[a]P in the case of Brazilian sample, was sufficient to elicit a response in YG5161, mutagenicity was detected at a dose as low as 1 m3/plate (0.9 ng). This is probably caused by nitro-compounds that have been shown to be even more potent than B[a]P for YG5161. It seems that the mutagenicity of B[a]P present in PM is not detectable even with the use of YG5161 unless more efficient separation to remove the nitro-compounds from the PAH extract is performed.

  • 49. Unosson, Jon
    et al.
    Blomberg, Anders
    Sandström, Thomas
    Muala, Ala
    Boman, Christoffer
    Nyström, Robin
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Mills, Nicholas L.
    Newby, David E.
    Langrish, Jeremy P.
    Bosson, Jenny A.
    Exposure to wood smoke increases arterial stiffness and decreases heart rate variability in humans2013In: Particle and Fibre Toxicology, ISSN 1743-8977, E-ISSN 1743-8977, Vol. 10, p. 20-Article in journal (Refereed)
    Abstract [en]

    Background: Emissions from biomass combustion are a major source of indoor and outdoor air pollution, and are estimated to cause millions of premature deaths worldwide annually. Whilst adverse respiratory health effects of biomass exposure are well established, less is known about its effects on the cardiovascular system. In this study we assessed the effect of exposure to wood smoke on heart rate, blood pressure, central arterial stiffness and heart rate variability in otherwise healthy persons. Methods: Fourteen healthy non-smoking subjects participated in a randomized, double-blind crossover study. Subjects were exposed to dilute wood smoke (mean particle concentration of 314 +/- 38 mu g/m(3)) or filtered air for three hours during intermittent exercise. Heart rate, blood pressure, central arterial stiffness and heart rate variability were measured at baseline and for one hour post-exposure. Results: Central arterial stiffness, measured as augmentation index, augmentation pressure and pulse wave velocity, was higher after wood smoke exposure as compared to filtered air (p < 0.01 for all), and heart rate was increased (p < 0.01) although there was no effect on blood pressure. Heart rate variability (SDNN, RMSSD and pNN50; p = 0.003, p < 0.001 and p < 0.001 respectively) was decreased one hour following exposure to wood smoke compared to filtered air. Conclusions: Acute exposure to wood smoke as a model of exposure to biomass combustion is associated with an immediate increase in central arterial stiffness and a simultaneous reduction in heart rate variability. As biomass is used for cooking and heating by a large fraction of the global population and is currently advocated as a sustainable alternative energy source, further studies are required to establish its likely impact on cardiovascular disease.

  • 50.
    Westerholm, R
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Testresultat från FFV fordon körda på etanol- inblandad bensin: Svenska Luftvårdsföreningens höstseminarium2008Report (Other academic)
12 1 - 50 of 55
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf