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Mass absorption efficiency of light absorbing organic aerosols from source region of paddy-residue burning emissions in the Indo-Gangetic Plain
- Source :
- Atmospheric Environment. 125:360-370
- Publication Year :
- 2016
- Publisher :
- Elsevier BV, 2016.
-
Abstract
- The mass absorption efficiency (MAE) of light absorbing water-soluble organics, representing a significant fraction of brown carbon (BrC), has been studied in fine mode aerosols (PM2.5) from a source region (Patiala: 30.2 °N, 76.3 °E) of biomass burning emissions (BBEs) in the Indo-Gangetic Plain (IGP). The mass absorption coefficient of BrC at 365 nm (babs-365), assessed from absorption spectra of aqueous extracts, exhibits significant linear relationship with water-soluble organic carbon (WSOC) for day (R2 = 0.37) and night time (R2 = 0.77) samples; and slope of regression lines provides a measure of MAE of BrC (daytime: ∼0.75 m2 g−1 and night time: 1.13 m2 g−1). A close similarity in the temporal variability of babs-365 (for BrC) and K+ in all samples suggests their common source from BBEs. The babs-365 of BrC follows a power law (babs-λ ≈ λ−α; where α = angstrom exponent) and averages around 5.2 ± 2.0 M m−1 (where M = 10−6). A significant decrease in the MAE of BrC from the source region (this study) to the downwind oceanic region (over Bay of Bengal, Srinivas and Sarin, 2013 ) could be attributed to relative increase in the contribution of non-absorbing WSOC and/or photo-bleaching of BrC during long-range atmospheric transport. The atmospheric radiative forcing due to BrC over the study site accounts for ∼40% of that from elemental carbon (EC).
- Subjects :
- Total organic carbon
Atmospheric Science
Daytime
Mass absorption
010504 meteorology & atmospheric sciences
Absorption spectroscopy
Chemistry
Mineralogy
010501 environmental sciences
Radiative forcing
Atmospheric sciences
01 natural sciences
Mass attenuation coefficient
Biomass burning
Brown carbon
0105 earth and related environmental sciences
General Environmental Science
Subjects
Details
- ISSN :
- 13522310
- Volume :
- 125
- Database :
- OpenAIRE
- Journal :
- Atmospheric Environment
- Accession number :
- edsair.doi...........2579b27d6e791c100143ca287ae0e45b