AI Summary & Key Takeaways
AI InsightA significant abundance of organic aerosols and mineral dust in presence of high moisture content and their mixing over IGP has implications to perturbation in regional scale radiative forcing
📌 3 Key Takeaways
Özet
Ambient PM2.5 (n = 42) samples have been collected during a weak South-west (SW) monsoon (July‒September, 2015) from central part of the Indo-Gangetic Plain (IGP; at Kanpur). Organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), water-soluble inorganic species (WSIS) and metals have been measured in this study. Air-mass back trajectory (AMBT) analysis reveals atmospheric transport from three major pathways indicated as Type-1 (n = 24; traversing through western region), Type-2 (n = 8; traversing eastern region) and Type-3 (n = 10; terrestrial air-masses). Total carbonaceous aerosols (TCA), mineral dust (MD) and WSIS in Type-1 air-mass contributed 18.7 ± 8%, 40.3 ± 14.5% and 35.2 ± 13.4%, respectively to the PM2.5 mass. TCA, MD and WSIS mass fractions constituted 27.1 ± 13.2%, 29.1 ± 7.9% and 34.9 ± 10.7% in Type-2 air-mass and 25.2 ± 14.1%, 34.6 ± 14% and 33.3 ± 9.8% in Type-3 air-mass, respectively. Mineral dust percentage fraction and composition (based on Fe/Al ratio) suggests significant differences between Type-1 and Type-2 air-masses. Based on statistical two-tailed t-test, the mineral dust composition of Type-1 versus Type3 and Type-2 versus Type-3 air-masses look near similar. However, average mass ratios of OC/EC (6.2–6.4), WSOC/OC (≈0.50; exception being difference in Type-2 versus Type-3) and K+ BB/OC (0.05–0.07; K+ BB: biomass burning derived potassium) look near similar in PM2.5 associated with all the three air-masses; indicating carbonaceous aerosols from well-mixed sources with dominant contribution from biomass burning emission. A significant abundance of organic aerosols and mineral dust in presence of high moisture content and their mixing over IGP has implications to perturbation in regional scale radiative forcing