Impact of COVID-19 Lockdown on Air Quality and Source Identification During Lockdown in Andhra Pradesh, India

Lockdown had a significant influence on both local and global economies, and it will take some time for things to return to normal. However, one major advantage of this lockdown has emerged as an improvement in the air quality of cities around the world. In the current study, the impact of the COVID-19 lockdown on the improved air quality is assessed over the four major cities (Amravati, Rajamahendravaram, Tirupati, and Vizag) of Andhra Pradesh (AP). The study results emphasized a substantial reduction in the levels of PM2.5 in the range (40-60%), PM10(20-40%), NO2(26-74%), SO2(5-26%), CO(6-82%) over the study regions on comparison between before and after lockdown periods. The average Air Quality Index (AQI) majorly declined in Vizag (34%), followed by Amaravati (26%), Tirupati (31%), and slightly in Rajamahendravaram (4%). With the decrease in the AQI, it is observed that there is an increase in southwest monsoon rainfall intensity over the AP state.Further, this study identified the potential sources impacting during lockdown towards study areas with the application of HYSPLIT Back Trajectory Analysis (BTA). The analysis revealed that the primary sources were predominantly from the Bay of Bengal (BOB), within the state, and partially from neighbouring regions Odisha, Tamil Nadu, Chhattisgarh, and Telangana.