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  • 1.
    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.

  • 2.
    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)
  • 3.
    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.

  • 4.
    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.

  • 5.
    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.

  • 6.
    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.))
  • 7.
    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.))
  • 8.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Determination of dibenzopyrenes in standard reference materials (SRM) 1649a, 1650, and 2975 using ultrasonically assisted extraction and LC-GC-MS2006In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 384, no 2, p. 438-447Article in journal (Refereed)
    Abstract [en]

    A method has been developed for analysis of the highly potent polycyclic aromatic hydrocarbon (PAH) carcinogens dibenzo(a,l)pyrene, dibenzo(a,h)pyrene and dibenzo(a,i)pyrene (molecular weight 302) present in small amounts in diesel and air particulate materials. The method can also be used for analysis of the PAH benzo(a)pyrene, coronene and perylene, for which reference and certified values are available for the Standard Reference Materials used for validation of the method: SRM 1649a (Urban dust) and SRM 2975 (Diesel particulate matter). The only NIST values that have been published for these dibenzopyrene isomers in the analyzed SRMs are reference values for dibenzo(a,i)pyrene and dibenzo(a,h)pyrene in SRM 1649a. The concentrations determined in the SRMs were in good agreement with reported NIST-certified and reference values and other concentrations reported in the literature. The Standard Reference Material 1650 (Diesel particulate matter) was also analyzed. The method could not, however, be validated using this material because certification of SRM 1650 had expired. The method is based on ultrasonically-assisted extraction of the particulate material, then silica SPE pre-separation and isolation, and, separation and detection by hyphenated LC-GC-MS. The method is relatively rapid and requires only approximately 1-5 mg SRM particulate material to identify and quantify the analytes. Low extraction recoveries for the analytes, in particular the dibenzopyrenes, when extracting diesel SRMs 2975 and 1650 resulted, however, in the dibenzopyrenes being present in amounts near their limit of quantifications in these samples. The method’s limit of quantification (LOQ), based on analyses of SRM 1649a, is in the range of 10-77 pg. By use of this method more than 25 potential PAH isomers with a molecular weight of 302 could be separated.

  • 9.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Methods for Determination of Benzo(a)pyrene and High Molecular Weight (>300 Da) Polycyclic Aromatic Hydrocarbons in Particulate Matter from Ambient Air and Vehicle Exhausts2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Air pollution with particulate matter (PM) raises considerable concern because of its adverse effects on human health. For this reason, and because the mechanisms of PM toxicity are not fully known, there is an urgent need to determine the chemical constituents of atmospheric PM, especially PM emanating from traffic - a major source of urban PM.

    This thesis describes analytical methods that have been developed for determining polycyclic aromatic hydrocarbons (PAHs) in ambient air and vehicle exhaust PM, focusing particularly on benzo(a)pyrene (B(a)P) and the dibenzopyrenes: dibenzo(a,l)pyrene, dibenzo(a,e)pyrene, dibenzo(a,i)pyrene and dibenzo(a,h)pyrene. Trace amounts in complex matrices have been met by coupling parts or the entire clean-up step using liquid chromatography on-line with the analysis step using gas chromatography-mass spectrometry into one automated system.

    Application of the methodology, using either ultrasonic assisted extraction (USE) or accelerated solvent extraction (ASE), to a National Institute of Standards and Technology (NIST) urban air standard reference material (SRM) yielded comparable or higher concentrations than the assigned NIST values, validating the approach. However, ASE provided higher extraction yields from diesel particulate SRMs than USE, and ASE of diesel SRMs generally yielded higher concentrations than the corresponding NIST values.

    Concentrations of dibenzopyrenes in Stockholm air PM, and gasoline- and diesel-fuelled vehicle emissions (ng/km), are reported for the first time. When adjusted in terms of their relative carcinogenic potencies, the dibenzopyrenes were found to pose greater carcinogenic hazards than B(a)P, indicating that the current use of B(a)P as a marker probably leads to underestimates of the carcinogenicity of PAHs in ambient air.

    The developed methods also worked well for analyzing larger molecular weight PAHs: more than 60 and 170 potential PAHs were detected in ambient air PM and diesel PM, respectively.

  • 10.
    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.

  • 11.
    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 highly carcinogenic dibenzopyrene isomers in particulate emissions from two diesel- and two gasoline-fuelled light-duty vehicles2009In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 43, no 25, p. 3883-3890Article in journal (Refereed)
    Abstract [en]

    Emission factors of particulate-bound Polycyclic Aromatic Hydrocarbons (PAHs) including benzo(a)pyrene and, for the first time, the highly carcinogenic dibenzo(a,l)pyrene, dibenzo(a,e)pyrene, dibenzo(a,i)pyrene and dibenzo(a,h)pyrene have been determined in exhausts from two diesel- (DFVs) and two gasoline-fuelled light-duty vehicles (GFVs) operated in the Urban (AU), Rural Road (AR) and Motorway (AM) transient ARTEMIS driving cycles. The obtained results showed the DFVs to emit higher amounts of PAHs than the GFVs per km driving distance at low average speed in the AU driving cycle, while the GFVs emitted higher amounts of PAHs than the DFVs per km driving distance at higher average speeds in the AR and AM driving cycles. Furthermore, the study showed an increase in PAH emissions per km driving distance with increasing average speed for the GFVs with the opposite trend found for the DFVs. The GFVs generated particulate matter with higher PAH content than the DFVs in all three driving cycles tested with the highest concentrations obtained in the AR driving cycle. Dibenzo(a,l)pyrene was found to be a major contributor to the potential carcinogenicity accounting for 58–67% and 25–31% of the sum added potential carcinogenicity of the measured PAHs in the emitted particulate matter from the DFVs and GFVs, respectively. Corresponding values for benzo(a)pyrene were 16–25% and 11–40% for the DFVs and GFVs, respectively. The DFVs displayed higher sum added potential carcinogenicity of the measured PAHs than the GFVs in the AU driving cycle with the opposite trend found in the AR and AM driving cycles. The findings of this study show the importance of including the dibenzopyrenes in vehicle exhaust chemical characterizations to avoid potential underestimation of the carcinogenic activity of the emissions. The lower emissions and the lower sum added potential carcinogenicity of the measured PAHs found in this study for the GFVs compared to the DFVs in the AU driving cycle indicate the GFVs to be preferred in dense urban areas with traffic moving at low average speeds with multiple start and stops. However, the obtained results suggest the opposite to be true at higher average speeds with driving at rural roads and motorways. Further studies are, however, needed to establish if the observed differences between GFVs and DFVs are generally valid as well as to study the effects on variations in vehicle/engine type, ambient temperature, fuel and driving conditions on the emission factors.

  • 12.
    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.

  • 13.
    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.

  • 14. 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.

  • 15. 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.

  • 16. 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.

  • 17. 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.

  • 18.
    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

  • 19.
    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.

  • 20.
    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.

  • 21.
    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%.

  • 22. 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.

  • 23. 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/).

  • 24.
    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.

  • 25.
    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.

  • 26. 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.

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