State of air pollutants and related health risk over Haryana India as viewed from satellite platform in COVID-19 lockdown scenario

COVID-19 driven lockdown has affected air quality worldwide. Changes in air pollutants concentration, Air Quality Index (AQI), and associated Excess Health Risk (ER%) were assessed using satellite data of before (2019), and during (2020) COVID-19 periods in the industrially, agriculturally developed and highly populated area of Haryana in the northern region of Indo-Gangetic Plains. Parameters such as Aerosol Optical Depth (AOD), Particulate matters (PM), Sulphur Di-Oxide (SO(2)), Nitrogen Di-Oxide (NO(2)), Carbon Mono-oxide (CO), and Methane (CH(4)) were derived using satellite data and validated using ground-based observations (n = 23). The coefficient of correlation (r) 0.91, 0.90, 0.95, 0.73, 0.81 and 0.80 were established with AOD, PM(2.5), PM(10), SO(2), NO(2) and CO, respectively. Significant reduction (p < 0.005) in the concentration of air pollutants, viz. 38% in AOD, 55% in PM(2.5), 61% in PM(10), 31% in SO(2), 10% in NO(2), 5% in CO and 1% in CH(4) were observed during lockdown. Significant (p < 0.00) improvement in air quality was observed due to a 44% reduction in pollution level, which led to the reduction in ER% by 71%, which is quite significant. AQI and ER% from satellite and ground showed a high r(2) i.e. 0.88 and 0.99 respectively, suggesting the potential application of satellite data for periodic AQI and ER% assessment.