Non-uniform effect of COVID-19 lockdown on the air quality in different local climate zones of the urban region of Kochi, India

Abstract

Deterioration of ambient air quality associated with urbanisation is a serious concern in many parts of the world. In India, air pollution, primarily due to particulate matter, has increased exponentially in the last few decades due to rapid urbanization, industrialization and population growth. This study investigates the non-uniform influence of COVID-19 lockdown on the ambient air quality of three distinct local climate zones (LCZs) within the urban region of Kochi (Kerala, India). The analysis of the air pollutant data of the ambient air quality monitoring stations during the pre-lockdown (PRLD), lockdown (LD) and post-lockdown (PTLD) periods of 2021 implies the significance of lockdown measures in the improvement of urban air quality. The air quality index (AQI) exhibits characteristic variability in different LCZs and contrasting behaviour between the LD period of 2020 and 2021, primarily due to the differences in the lockdown restrictions and strategies as well as the influence of local climatic factors. This study highlights the need for multiple monitoring stations in the urban regions with respect to different LCZs to identify the urban air quality hot spots.

Impact of COVID-19 Lockdown on Ambient Air Quality in the Southwest Coastal Urban Regions of India

“…However, the concentration of various air pollutants returned to its original level (i.e., PRLD) after relaxing the lockdown measures during the PTLD period. Thomas et al ( 2022 ) noted such behaviour of air pollutants in the Kochi urban area of Kerala. However, most of the pollutants recorded at KN show a continuation of the declining trend of the LD period in the PTLD period also.…”

Impact of COVID-19 Restrictions Liberalization on Air Quality: A Case Study of Chongqing, Southwest China

“…. A study in the southwest coastal region of India found that the changes in PM 2.5 , PM 10 , NO 2 and O 3 concentrations relative to the lockdown period ranged from + 11.5% to + 38.3%, from + 1.3% to + 36.0%, from − 5.1% to + 46.1% and from − 21.2% to + 4.1%, respectively(Thomas et al, 2023). The study conducted in Campania, Italy revealed an increase in pollutant concentrations at all stations following the lifting of lockdown measures with signi cant changes observed for NO 2 concentrations ranging between + 32% to + 63%(Cardito et al, 2023).…”