Characteristics, Dynamics, and Impact of the Thar Desert Dust Storms on Air Quality over Northern India

Abstract

In the present study, a pre-monsoon dust storm event (14 May 2018 ± 2 days), originating from Thar Desert (Rajasthan state), spread to north Indian states- Haryana, Delhi, and Uttar Pradesh is selected. Satellite observations, climate model reanalysis datasets, and ground monitoring station and meteorological parameters were used to study the dust storm event and its impact on air quality of the northern region of India against a non-dust storm background reference (viz., 25 May 2018 ± 1 day). We include dust column mass density (DCMD total and DCMD PM2.5), and find 3-5 times higher air column dust loading (maximum 3.9 g/m2) during the event, against dust levels (~0.2-0.6 g/m2) during the background non-dust storm period. NOAA HYSPLIT 72-hour forward trajectories show air-mass transport from the Thar Desert towards IGP. Aerosol Optical Depth (AOD)> 2 in the affected region indicates a high residence time of dust aerosols. DCMD is used to show the 3-hourly progression of the dust storm (initiation, spread, and gradual dissipation). Moreover, hourly dust loading in the air (DCMD) and particulate matter (PM10 and PM2.5) ground-based observations over Jodhpur (Rajasthan), Rohtak (Haryana), Delhi (NCT of Delhi), and Lucknow (Uttar Pradesh) cities, show severe worsening of the already poor air quality of the region. Lastly, local spatial correlations are plotted to understand the spatial associations, variabilities, and local feedback between the variables- DCMD, AOD, 2m air temperature, precipitation, and wind speed.