Abstract
Novel Coronavirus disease (COVID-19), after being identified in late December 2019 in Wuhan city of China, spread very fast and has affected all the countries in the world. The impact of lockdowns on particulate matter during the lockdown period needs attention to explore the correlation between anthropogenic and natural emissions. The current study has demonstrated the changes in fine particulate matter PM2.5, PM10 and their effect on air quality during the lockdown. The air quality before the lockdown was low in New Delhi (India) and Riyadh (Saudi Arabia), among major cities worldwide. The air quality of India is influenced by dust and sand from the desert and surrounding areas. Thus, the current study becomes important to analyse changes in the air quality of the Indian sub-continent as impacted by dust storms from long distances. The result indicated a significant reduction of PM2.5 and PM10 from 93.24 to 37.89 μg/m3 and from 176.55 to 98.87 μg/m3 during the lockdown period as compared to pre lockdown period, respectively. The study shows that average concentrations of PM10 and PM2.5 have declined by -44% and -59% during the lockdown period in Delhi. The average value of median PM10 was calculated at 33.71 μg/m3 for Riyadh, which was lower than that value for New Delhi during the same period. The values of PM10 were different for pre and during the lockdown periods in Riyadh, indicating the considerable influence on air quality, especially the concentration of PM10, from both the natural (sand and dust storms) and the anthropogenic sources during the lockdown periods. However, relatively smaller gains in the improvement of air quality in Riyadh were correlated to the imposition of milder lockdown and the predominance of natural factors over the anthropogenic factors there. The Air Quality Index (AQI) data for Delhi showed the air quality to be ‘satisfactory’ and in the green category during the lockdown period. This study attempts to better understand the impact of particulate matter on the short- and long-term air quality in Delhi during the lockdown. This study has the scope of being scaled up nationwide, and this might be helpful in formulation air pollution reduction and sustainable management policies in the future.
Highlights
The COVID-19 originated from the city of Wuhan in China, supposedly in December 2019after the detection of the first COVID-19 positive case (Bashir et al, 2020; Chen et al, 2020)
The present study shows that average concentrations of PM2.5 and PM10 declined by -59% and -44%, respectively, during the lockdown period in Delhi
The present study finds no major changes in particulate matter pre- and post-lockdown periods in Riyad, Saudi Arabia, which could be due to frequent dust events during the same period
Summary
The COVID-19 originated from the city of Wuhan in China, supposedly in December 2019after the detection of the first COVID-19 positive case (Bashir et al, 2020; Chen et al, 2020). COVID-19 has become a pandemic impacting the entire population. Several studies have confirmed high transmissivity of the Corona Virus, which affects many people within a short period (Gautam and Trivedi, 2020; Sharma et al, 2020). The pandemic has impacted the mental wellbeing of a huge proportion of the population in the form of distress, stress, and depression, as revealed by several studies (Abbas et al, 2019; Aqeel et al, 2021; Lebni et al, 2021; Local Burden of Disease, 2021). Su et al (2021b) reported that COVID-19 induced unprecedented illness perception has caused mental disorders, including anxiety and depression, which have severely impacted individuals’ mental health. A study reported the relationship between the COVID-19 infection and vaccine non-adopters in terms of detection of the number of new corona cases (Su et al, 2020). Better social and educational support to vulnerable individuals might help explain differences in the scale of observed mental health problems across countries. (Azadi et al, 2021; Abbas., 2021; Su et al, 2021a; Azizi et al, 2021; Abbas et al, 2019)
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