Characteristics, dynamics, and impact of the Thar Desert dust storms on air quality over northern India

In this study, a pre-monsoon dust storm (14 May 2018 +/- 2 days), originating from the Thar Desert (Rajasthan state) that spread to north Indian states-Haryana, Delhi, and Uttar Pradesh is selected. We leverage satellite (MODIS, GPM_IMERG), climate model reanalysis (MERRA-2), and ground monitoring station (CPCB, IMD, AERONET) observations to study the selected dust storm event, and its impact on air quality of northern India against a background reference (25 May 2018 +/- 1 day). We include dust column mass density (DCMD total and PM2.5) datasets, and find 3-5 times higher air column dust loading (maximum 3.9 g/m(2)) during the event, against background dust levels (similar to 0.2-0.6 g/m(2)). NOAA HYSPLIT 72-h forward trajectories show air-mass transport from the Thar Desert towards The Indo-Gangetic Plains (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. We employ local spatial correlations to understand the significant statistical associations, variabilities, and feedbacks between-DCMD, AOD, 2 m air temperature, precipitation, and wind speed. The study highlights the use of gridded DCMD datasets, and geospatial techniques, as an innovative proposal for estimating the impact of dust in data-poor regions. [GRAPHICS] .