Regional Air Quality: Forest Fires Impacts of SO2 Emissions on Air Pollutants in the Himalayan Region of Uttarakhand, India

Abstract

Sulfur dioxide (SO2) is a toxic with adverse health effects on respiratory tract, eyes, mucous membranes and skin. In the present study, the continuous ground-based SO2 monitoring has planned over Srinagar Garhwal Valley of Uttarakhand. In the monsoon (M-2018), Post-monsoon (PoM-2018), Winter (W-2019) & Pre-monsoon (PrM-2019) & & M-2019 have high SO2 concentrations (3.66 ± 2.05 µg/m3, 5.54 ± 2.23 µg/m3, 6.42 ± 1.79 µg/m3, 7.56 ± 3.53 µg/m3 6.45 ± 3.49 µ g/m3) at1900 LT, 2000 LT, 1800 LT, 1900 LT &1900 LT attributed mainly due to biomass burning and long-range transportation of pollutants. A drastic change in the SO2 concentration has been observed from 4.81 to 17.39 µg/m3 during May 2019 with a strong correlation of 0.61 with fire-counts during extensive forest fire. Whereas Jul 2018 (1.07 ± 0.82 µg/m3) showed the lowest SO2 concentration due to wet scavenging process. Temperature, humidity and wind speed have significant correlation with SO2 in different season. Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model trajectories and cluster analysis indicate the transportation of air mass from the Gulf region, Sahara Desert, Pakistan, Afghanistan to Srinagar with a significant contribution of 40.43–72.29% air mass. We have also observed weekend effects (reduction in the pollutant concentration) in Jul 2018, Sep 2018, Feb 2019, Apr 2019 and May 2019.