Impact of COVID-19 Lockdowns on Air Quality in Haryana: A Multi-Year Analysis of PM 2.5 , PM 10 , NO x , CO, and Ozone

Abstract

Background: The COVID-19 pandemic and nationwide lockdown in India during 2020, led to an unprecedented decrease in anthropogenic activities, offering a rare chance to assess the effect of anthropogenic activities on ambient air quality. Objective: To understand the impact of COVID-19 lockdown on the main air pollutants of Haryana, India and to compare the air quality condition before, during, and after the COVID-19 lockdown. Methods: Air quality parameters: PM 2.5 , PM 10 , NOx, CO and O₃ were obtained from Continuous Ambient Air Quality Monitoring Stations (CAAQMS) operated by Central Pollution Control Board (CPCB). Data of ten parliamentary constituencies were taken from across Haryana and analysed in the time period of 2019-2022. Pollutant levels in 2020 during four lockdown periods were compared to those in 2019, 2021 and 2022. Average concentrations were computed daily and temporal trends were analyzed to detect changes in pollutant concentrations. The results in this thesis showed significant reductions in PM 2.5 , PM 10 , NOₓ and CO levels during the lockdown period. During the first phase of the lockdown, a sharp drop in traffic, industry activity and construction, led to a decrease in PM 2.5 concentrations of almost 50%, and in NOₓ levels of more than 60%. Similarly, there were substantial decreases of PM 10 and CO from pre-lockdown periods. The behavior of the ozone concentration varied significantly as a result of some complex photochemical processes, involving the emissions of precursors and the atmospheric conditions. But concentrations increased slowly over the next few years following the pandemic (2021-2022) towards pre-pandemic concentrations. Conclusion: The study clearly shows that anthropogenic activities have a significant impact on the air quality in Haryana. The rebound in pollutant concentrations after the lockdown shows that sustainable long-term strategies for air pollution control are necessary, such as developing clean transportation systems, setting tighter limits on industrial emissions, and improving urban planning Solutions.