Source Impact Analysis Using Char-EC/soot-EC Ratios in the Central Indo-Gangetic Plain (IGP) of India

Manisha Mishra, U.C. Kulshrestha
2021 Aerosol and Air Quality Research  
8 This study reports one year (December 2016-November 2017) observations of carbonaceous 9 aerosols in fine particulate matter (fPM; dia. < 2.5µm, n = 102 samples) over an urban location 10 (Prayagraj) in central Indo-Gangetic Plain (IGP). The fPM concentrations exhibited a very large 11 variability ranging from 22-367 (Avg. ± SD: 149 ± 87) µg m -3 during the entire study period. The 12 carbonaceous aerosols (Organic Carbon (OC), Water soluble OC (WSOC) and Elemental Carbon 13 (EC)) constituted
more » ... 3 (EC)) constituted about 40% of the annual fPM mass. Furthermore, based on several diagnostic 14 ratios (EC/fPM, OC/EC, char-EC/soot-EC, and WSOC/OC), the characteristic features of 15 carbonaceous aerosols were inferred to be significantly different in each season. The variation in 16 the abundance pattern of carbonaceous aerosols appears to have influence of emission sources, 17 seasonal meteorology, and atmospheric chemistry. The trajectory analysis at the sampling site has 18 revealed that higher concentration of fPM and carbonaceous aerosols, mainly during the post-19 monsoon and winter season, was associated with the northwesterly air masses originated from the 20 northwestern part of India. However, during summer and monsoon seasons the study site was 21 likely to have influence from air masses of mixed origins (continental/marine) with the dominance 22 of local anthropogenic sources. The char-EC/soot-EC ratio coupled to OC/EC ratio has been 23 utilized in this study for source impact identification. Accordingly, the cross plots of char-EC/soot-24 EC and OC/EC ratio indicated the more of influence biomass burning during winter and post-25 monsoon season. However, during the summer and monsoon season, the cross plot indicated the 26 predominant impact of fossil-fuel combustion sources. This study highlights the utility of char-27 EC/soot-EC ratio as a better indicator to trace out the impact of biomass burning and fossil-fuel 28 combustion sources of carbonaceous aerosols compared to OC/EC over the IGP region. 29 30
doi:10.4209/aaqr.200628 fatcat:mr56oftbqjenbbqh63mharkxeu