Water-soluble organic carbon aerosols during a full New Delhi winter: Isotope-based source apportionment and optical properties
Number of Authors: 6
2014 (English)In: JOURNAL OF GEOPHYSICAL RESEARCH - ATMOSPHERES, ISSN 2169-8996, Vol. 119, no 6, 3476-3485 p.Article in journal (Refereed) Published
Water soluble organic carbon (WSOC) aerosol is a major constituent (~ 20-80% of the total organic carbon) of the ‘brown cloud’ that shades the Indian Subcontinent. Due to the multiple formation pathways (both primary and secondary), the emissions sources of WSOC are particularly poorly constrained. In this study, we present radiocarbon constraints on the biomass vs fossil sources of WSOC in PM2.5 for the 2010/11 winter period for the megacity Delhi, situated in the center of the heavily polluted Indo-Gangetic Plain. The fossil contribution (22±4%) to WSOC in Delhi is found to be similar to fossil fraction at Indian background sites. Stable carbon analysis shows that Delhi WSOC is more depleted in 13C relative to what is found at receptor sites, indicating that near-source WSOC is less affected by atmospheric aging. In addition, the light absorptive properties of WSOC were investigated. The mass absorption cross section at 365 nm (MAC365) ranged 1.1 – 2.7 m2/g, and the corresponding absorption Ångström exponent (AAE) ranged between 3.1 and 9.3. Using a simplistic estimate of the relative absorptive radiative forcing was found to be 6 – 42 % relative to that of black carbon. Taken together this near-source study emphasize the importance of taking into account the complex transformations of WSOC during air mass transport, as compared with regional receptor sites.
Place, publisher, year, edition, pages
2014. Vol. 119, no 6, 3476-3485 p.
water soluble organic carbon, New Delhi, carbon isotopes, source apportionment, light absorption properties, aerosol aging
Environmental Sciences Analytical Chemistry
Research subject Applied Environmental Science
IdentifiersURN: urn:nbn:se:su:diva-89179DOI: 10.1002/2013JD020041ISI: 000336046600045OAI: oai:DiVA.org:su-89179DiVA: diva2:616327
FunderSida - Swedish International Development Cooperation Agency, AKT-2010-038Formas, 214-2009-970Knut and Alice Wallenberg Foundation