Effect of lockdown on air pollutants during COVID – 19 over Hyderabad

Venkateswara Rao Polisetty

doi:10.17485/ijst/v13i32.1411

Abstract

Objective: To understand the temporal characteristics of air pollutants during lockdown and to assess the impact of them on air quality. Method: We have analyzed the ambient monitoring data, from Central Pollution Control Board (CPCB), of air pollutants from 27th January to 12th July 2020 to compare prelockdown (27th Jan to 22nd March), during lockdown (23rd March to 17th May) and post lockdown (18th May to 12th July) effects over six stations in Hyderabad. Further, to understand the significant differences in PM concentrations we have evaluated rate of change (ROC) over a defined period of time. Pearson correlation analysis was used as an indicator of the relation between PM2.5 and PM10 for the study period. Findings: Our results show a significant decline in PM2.5 (27%) and PM10 (34%) concentrations during lockdown. This indicates positive effect of lockdown on air quality over Hyderabad. The contribution of PM2.5 in PM10 (46%) during lockdown remains same when compared to previous years though the concentrations have decreased. The PM2.5 was highly correlated with PM10 over all the stations. A substantial decrease in PM2.5 (27%) and PM10(39%) compared to the same period of previous years were observed. Apart of particulate matter the concentration of NO2 decreased by 33% during lockdown. Another noticeable point observed is that the concentrations of CO and SO2 showed a marginal decrease and they remained below permissible limits (NAAQS) during study period. Novelty / Recommendations: Overall, this study may be helpful to understand how air pollution is affected during COVID – 19 pandemic and provide important signs regarding the control of emissions by subsequently implementing stringent rules, like complete lockdown at least one day per week, imposing traffic rules, encouraging online teaching, digital shopping etc., to heal and save the environment. Keywords: Covid-19; lockdown; air pollutants; particulate matter; air quality

Highlights

The rapid spread of coronavirus disease (COVID-19) was first identified in Wuhan, China
In order to assess and quantify the impact of lockdown on air pollution over Hyderabad, we have studied the variations of air pollutants (PM2.5, PM10 NO2, SO2, O3 and Carbon monoxide (CO)) in this paper
It clearly indicates that the number of days with concentration greater than100 μg/m3 is reduced by 40% during lockdown when compared with pre-lockdown

Summary

Introduction

The rapid spread of coronavirus disease (COVID-19) was first identified in Wuhan, China. The Indian authorities, for preventing the spread of the disease and securing the health and safety of Indian citizens, have decided to implement the first nationwide lockdown (Janata Curfew) for 14 hrs on 22nd March, followed by first phase of lockdown form 24th March to 14th April (21 days) Such lockdown was unique in India where all air and road transport was banned. The city is having a wide spread Industrial Development Areas (IDA) and a vast growth in population ~10 million, contributing to the anthropogenic activities which seriously play an important role in air pollution In this context, the main objective of the present study is to assess the variations of PM2.5, PM10, CO, O3, NO2 and SO2 concentrations in the ambient air of Hyderabad city for pre, during and post lockdown periods and to quantify the effect of lockdown on air pollution

Data details

Literature survey

Effect of lockdown on air pollutants

Conclusions