Temporal and spatial variability of carbonaceous species (EC; OC; WSOC and SOA) in PM2.5 aerosol over five sites of Indo-Gangetic Plain

A year-long offline based study was performed at five sites of Indo-Gangetic plain to get the spatio-temporal variation in elemental carbon (EC), organic (OC), water-soluble (WSOC) and secondary aerosol (SOA) PM2.5 fraction. OC constitutes ~70–90% total with high fraction (60–70%) during winter, except Hisar. The change concentration insignificant summer, whereas increased by 75–85%. relatively OC/EC ratio (7–11) OC/K+ (10–52) winter post-monsoon suggest dominance biomass burning from wood fuel agricultural waste. EC is nearly constant over seasons all suggesting dominant presence traffic-originated throughout year. Interestingly, a low correlation (~0.3) between IITD IITMD indicates their source different origins. Exceptionally, daytime slightly higher than night time However, other showed opposite trend. significant linear relationship WSOC suggests contribution SOA. paired t-test results indicate much origin regional nature. contributed 30–60% across IGP, summer it varied 20 40%. SOA estimated EC- tracer method has highest (~138 ?g/m3) among peaked post-monsoon.