Abstract
Among the numerous anthropogenic pollutants, nitrogen dioxide (NO2) is one of the leading contaminants mainly released by burning fossil fuels in industrial and transport sectors. This study evaluates the impact of COVID-19 lockdown on the growing trend of NO2 emissions in South Asia. Satellite imagery data of Sentinel-5 Precursor with Tropomi instrument was employed in this study. The analysis was performed using time series data from February–May 2019 and February–May 2020. The time frame from February–May 2020 was further divided into two sub-time-frames, i.e., from 1 February–20 March (pre-lockdown) and from 21 March–May 2020 (lockdown). Results show the concentration of NO2 pollutants over the region declined by 6.41% from February–May 2019 to February–May 2020. Interestingly, an increasing trend of NO2 concentration by 6.58% occurred during the pre-lockdown phase in 2020 (1 February–20 March) compared to 2019 (February–May). However, the concentration of NO2 pollutants reduced considerably by 21.10% during the lockdown phase (21 March–10 May) compared to the pre-lockdown phase in 2020. Furthermore, the country-specific detailed analysis demonstrates the significant impact of COVID-19-attributed lockdown on NO2 concentration in South Asia.
Highlights
Environmental effects are one of the major factors affecting human health [1]
The results presented a negative association of temperature and climate with local transmission ratio (LTR) and LCPC
10 depicts NO2 pollutants with daily maximum values from February–May 2020 reprerepresented by a solid blue line and February–May 2019 shown by a solid green line
Summary
Environmental effects are one of the major factors affecting human health [1]. Monitoring air quality is vital for ecosystems and public health. Air pollutants such as nitrogen dioxide (NO2 ), ozone (O3 ), carbon monoxide (CO), and sulfur dioxide (SO2 ). Are contaminating the air at unprecedented rates, compromising public health [2]. A significant number of deaths are caused by air pollution each year and the situation is becoming worse daily. Around 7 million annual deaths reported by health authorities are due to the superfluous presence of NO2 and other pollutants in the atmosphere [5]. The emissions of NO2 declined significantly during COVID-19 lockdown period—when restrictions caused small enterprises, factories, and transport to shut down—thereby improving air quality
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