Geospatial View of Air Pollution and Health Risk Over North Indian Region in COVID-19 Scenario

Air pollutant concentration, air quality index (AQI), and Excess risk (ER%) is assessed during January 2020 to June 2021 and in three scenarios including pre-lockdown, lockdown and post-lockdown based on 47 ground station data (during January 2020 to June 2020) distributed over northern part of India (including Delhi, Haryana, Punjab, part of Uttar Pradesh, and part of Rajasthan) using statistics and geographic information system (GIS) techniques. Daily and monthly variations of air pollutants (During January 2020 to June 2021) over the region showed a systematic pattern with high pollutant level during October and November while low during March, April (in dry period) and July–September (in wet period). In three scenarios viz. pre, during and post-lockdown the average concentration for PM(2.5) was 71.1 ± 45 µg/m(3), 39 ± 20 µg/m(3) and 40 + 17 µg/m(3), for PM(10) was 139 ± 72 µg/m(3), 96 ± 55 µg/m(3) and 105 ± 57 µg/m(3), for NO(2) was 28 ± 21 µg/m(3), 17 ± 13 µg/m(3) and 18 ± 12 µg/m(3), for NH(3) was 33 ± 24 µg/m(3), 25 ± 18 µg/m(3) and 29 ± 22 µg/m(3), for CO was 1 ± 0.65 mg/m(3), 0.7 ± 0.5 mg/m(3), and 0.7 ± 0.5 mg/m(3), for O(3) was 29 ± 20 µg/m(3), 39 ± 23 µg/m(3) and 39 ± 22 µg/m(3) and for SO(2) was 14 ± 11 µg/m(3), 14 ± 12 µg/m(3) and 12.5 ± 8.9 µg/m(3). Significant decrease in mean pollutants concentration, AQI and ER % was observed in lockdown period amid COVID-19. PM(2.5), PM(10), NO(2), NH(3) and CO decreased by 46%, 31%, 39%, 24% and 34%, respectively, in lockdown scenario as compared to the pre-lockdown scenario while the O(3) get increased. A decrease of 39% in AQI was observed as compared to pre-lockdown scenario; however, the difference was less when compared with post-lockdown scenario. The decrease in total ER% was 60.36% over the study area due to improvement in air quality over the region amid COVID-19 lockdown. The meteorological conditions in 2020 were found consistent with respect to 2019 and very less influence was observed on the concentration of air pollutants (less r(2) among the pollutants and meteorological parameters). SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12524-022-01520-z.