Impact of Covid-19 Pandemic Lockdown on temporal variation of air quality in Bengaluru City – A case study

Abstract

Abstract The current study examines the variation in air pollution in Bengaluru, India, considering the influence of the Covid-19 lockdown. The concentration of 8 air pollutants including Particulate matter, and air quality index (AQI) is analysed. A geospatial analysis is performed using QGIS software, to depict pollution variation, based on which, further a relative change in concentration of each pollutant and AQI is determined. Exceedance factor (EF) of pollutants from 2019 to 2022 is determined along with statistical correlation analysis. The lockdown was implemented in March 2020, followed by a series of uplifting, and imposing, the months of March, April, and May were chosen for analysing. The study discovered a maximum reduction in AQI of (58%). However, a significant rise is observed, post-lockdown in 2022. The EF results revealed that particulate matter PM10, PM2.5 and NO2 are the major pollutants that posed a serious threat, as few stations fell into the 'Critical’, pollution category, especially in 2019. During the research period, SO2, C6H6, and NH3 concentrations were below the prescribed levels. The correlation study revealed that the AQI was closely related to PM10 and PM2.5. Overall, PM10, surpassed acceptable norms and is a principal criterion pollutant responsible for AQI in Bengaluru.