Stable Isotopic and Chemical Characteristics of Bulk Aerosols during Winter and Summer Seasons at a Station in Western Coast of India (Goa)

Abstract

We measured stable isotopic and chemical characteristics of bulk aerosols collected at a coastal station in western India (Goa) between December 2009 and January 2011, to characterize lower tropospheric atmospheric conditions and their influence on particle chemistry during winter and summer seasons. Marked differences were observed in terms of sources and chemical compositions of bulk aerosols. The δ 15 N TN values of winter aerosols (10.8 ± 2.2‰, n = 10) indicate biomass burning contributions in the carbonaceous fraction, while significantly depleted δ 15 N TN values of summer aerosols (6.2 ± 2.3‰, n = 12) hints incorporation of marine N species. The δ 34 S TS showed depleted values during winter (5.0 ± 1.0‰, n = 10), which closely matched with those of typical urban polluted environments, while summer aerosols showed a systematic enrichment of δ 34 S TS (up to ~14‰ with average value 9.0 ± 2.8‰, n = 13); possibly due to incorporation of volatile dimethyl sulfide (DMS) and its precursor dimethylsulfoniopropionate (DMSP) emitted from the adjacent Arabian Sea. Likewise, δ 13 C TOC values showed ~2‰ enrichment in winter aerosols (-24.8 ± 0.4‰, n = 10) with respect to those of summer values, indicating presence of bio-fuel and coal burning contributions in carbonaceous fraction of winter aerosols. We also measured major ions (Na + , K + , Mg ++ , Ca ++ , NH 4 + , Cl -, Br -, NO 3 -, SO 4 -2 ) in water soluble fraction of aerosols to understand winter/summer changes in the atmospheric chemistry over this coastal area. This is the first ever dataset on triple isotopic characteristics of bulk aerosols at a coastal location of India showing signatures of continental bio-mass/biofuel burning influences during winter, whereas marine inventories (e.g., sea salt, DMS and mineral dust) appear to dominate chemical composition of summer aerosols.

Carbon isotope‐constrained seasonality of carbonaceous aerosol sources from an urban location (Kanpur) in the Indo‐Gangetic Plain

“…It is also worthwhile to mention that source‐specific stable carbon isotopic composition of TC from FF‐comb source used in this study is not from the IGP, which therefore introduces some uncertainty. However, source‐specific δ 13 C of FF‐comb from South Asia [ Aggarwal et al ., ; Agnihotri et al ., ; Agnihotri et al ., ] is consistent with the literature data [ Cao et al ., ; Ho et al ., ; Widory , ] and, therefore, may not bias the results in this study.…”

Variation of Stable Carbon and Nitrogen Isotopic Composition of PM10 at Urban Sites of Indo Gangetic Plain (IGP) of India

“…Widory et al (2004) reported the value of d 13 C 3.3 to 14.3 9.6 ± 2.8 2.8 to 11.0 6.8 ± 2.4 2.8 to 11.5 7.4 ± 2.7 lg C m -3 (TC) 13.1 to 125.9 53.0 ± 33.6 9.3 to 51.9 27.1 ± 13.2 9.1 to 98.2 32.6 ± 24.9 lg N m -3 (TN) 1.5 to 42.6 14.9 ± 10.8 2.3 to 36.6 9.8 ± 9.7 1.4 to 25.9 9.3 ± 8.2 TC/TN 4.8 to 20.2 9.8 ± 3.7 2.1 to 16.3 9.2 ± 4.0 4.4 to 25.9 11.1 ± 5.7 d 13 OC -26.6 to -24.9 -25.5 ± 0.4 -26.3 to -24.6 -25.3 ± 0.7 -27.3 to -25.0 -26.1 ± 0.7 lg OC m -26.5 ± 0.5 % indicates the other sources (fossil fuel, coal etc.,) of C in ambient urban area. Agnihotri et al (2015) discussed in detail about the end member isotopic values (d 13 C and d 15 N) of major typical sources. The analysis of OC and EC concentrations over Delhi, Varanasi and Kolkata are attributed to the combined effects of traffic emission and biomass burning (including wood burning and crop residue burning).…”

Comparative study of atmospheric water-soluble organic aerosols composition in contrasting suburban environments in the Iberian Peninsula Coast

“…in both PM 2.5 and PM 10 samples collected in A Coruña during winter. The lower δ 15 N values during summer in A Coruña could also hint a higher contribution of marine nitrogen species (with lighter δ 15 N) at this suburban location(Agnihotri et al, 2015).…”