Air Pollution And Covid-19: A Global Impact Study

The COVID-19 pandemic has had a significant impact on air pollution levels across the globe.

Lockdowns and other measures to curb the spread of the virus have resulted in a reduction in economic activity and human movement, leading to a decrease in emissions from various sources.

Studies have shown that there was a notable decline in the concentration of major air pollutants, such as PM2.5, PM10, NO2, SO2, and CO, during the COVID-19 lockdown periods. This led to a significant improvement in air quality in many countries, including China, India, the United States, and several European nations.

The reduction in air pollution levels has likely had a positive impact on public health, potentially saving more lives than were lost to COVID-19. However, the long-term sustainability of such measures and their impact on the global economy need to be considered.

Air pollution has decreased in many countries due to lockdown measures, such as China, India, the UK, and the US

The COVID-19 lockdown measures have had a significant impact on air pollution levels in many countries, including China, India, the UK, and the US.

China

China was the first country to implement a nationwide lockdown in response to the COVID-19 outbreak, with Wuhan being the initial epicentre of the pandemic. The lockdown measures in China led to a notable decrease in air pollution levels, particularly in Wuhan and other major cities. Nitrogen dioxide (NO2) levels, a toxic gas released from vehicle exhausts, witnessed a significant drop during the lockdown. According to a study, NO2 levels in Wuhan decreased by five times compared to the previous year. This reduction in NO2 levels can be attributed to the decline in vehicle emissions as a result of restricted mobility and lower economic activities during the lockdown.

India

India also imposed a stringent nationwide lockdown to curb the spread of COVID-19. The lockdown measures had a positive impact on air quality across various cities in India. There was a significant reduction in the concentration of particulate matter (PM2.5 and PM10) and other pollutants such as carbon monoxide (CO) and nitrogen dioxide (NO2). For example, in Delhi, the PM2.5 levels decreased by 41-53%, while in Mumbai, they dropped by 10-39%. The improvement in air quality was particularly notable in highly polluted regions, such as the Indo-Gangetic Plain (IGP).

The United Kingdom

The UK's COVID-19 lockdown measures also contributed to a decrease in air pollution levels. According to data from the UK's Automatic Urban and Rural Network (AURN), nitrogen dioxide (NO2) levels in cities across the UK dropped by over 40% compared to the previous five years. The most significant reduction was observed in Cardiff, with a 60% decrease in NO2 levels. Other cities, including Belfast, Birmingham, Glasgow, Leeds, Manchester, and Newcastle, experienced NO2 reductions ranging from 40% to 50%.

The United States

The COVID-19 lockdown measures in the US led to a decline in air pollution levels, particularly in major cities. A study by NASA confirmed a 30% reduction in atmospheric NO2 levels over the Northeastern US during the lockdown. Additionally, there were notable decreases in PM2.5 levels in cities such as San Jose, Las Vegas, and Los Angeles. The reduction in air pollution can be attributed to the decrease in vehicle emissions and economic activities during the lockdown.

There has been a significant reduction in the concentrations of different air pollutants, including PM2.5, PM10, NO2, and CO

The COVID-19 pandemic has led to a reduction in air pollution across the world. The lockdown restrictions have resulted in a decrease in the concentration of various air pollutants, including PM2.5, PM10, NO2, and CO.

The reduction in air pollution levels has been observed in many cities worldwide, with some cities showing more significant decreases than others. The decrease in air pollution levels is attributed to the reduction in human activities, such as vehicular emissions and industrial activities.

The impact of the lockdown on air quality has been studied in various regions, including India, China, Europe, and the United States. The studies have shown a decline in the concentrations of PM2.5, PM10, NO2, and CO during the lockdown period compared to previous years.

The reduction in air pollution has led to health and economic benefits, including the avoidance of premature deaths and economic gains. The avoided premature deaths due to reduced air pollution levels have been valued in billions of US dollars.

The impact of COVID-19 on air quality has been studied at various scales, including the city, regional, and country levels

At the city level, studies have been conducted in cities such as Wuhan, Beijing, and Delhi, all of which have shown significant improvements in air quality during lockdown periods. For example, in Wuhan, China, there was a fivefold decrease in tropospheric NO2 density during the lockdown in February 2020 compared to the previous year. In Delhi, India, there was a 40% reduction in the air quality index (AQI) during one month of lockdown, and in Kolkata, India, there was a 39% reduction in PM2.5 during lockdown compared to 2019.

At the regional level, studies have been conducted in regions such as the Indo-Gangetic Plain (IGP) in India, which has shown significant improvements in air quality during lockdown. For instance, in the IGP, air quality was reported to be below permissible limits after many decades.

At the country level, studies have been conducted in countries such as India, China, the United States, Italy, and Brazil, all of which have shown significant improvements in air quality during lockdown periods. For example, in China, there was a 17-50% reduction in PM2.5, PM10, CO, and NO2 during the lockdown, and in the United States, there was a 9-42% reduction in NO2 across various states.

The highest number of studies on the impact of COVID-19 on air quality have been conducted in Asia, followed by Europe and North America

The COVID-19 pandemic has led to a significant reduction in economic and transport activity worldwide. This has resulted in a notable decline in air pollution levels, with certain pollutants exhibiting more substantial reductions than others.

In Asia, a majority of the studies have been conducted in India and China, with a focus on cities like Delhi, Bangalore, Beijing, and Wuhan. The studies indicate a significant decrease in air pollutants such as PM2.5, PM10, NO2, and CO, with some cities showing reductions of over 50%. However, there has been a mixed response in ozone levels, with some cities experiencing increases.

In Europe, Italy and Spain have been the most extensively studied countries. The findings suggest reductions in pollutants such as NO2, NO, PM2.5, and PM10, with NO2 showing the most consistent and strong pattern of decline. Ozone levels, on the other hand, tended to increase as nitrous oxide levels dropped.

North America, including the United States and Canada, has seen studies primarily focused on urban areas. Similar to Europe, there have been substantial reductions in NO2, NO, CO, and PM2.5 levels. However, ozone levels have generally increased due to the decrease in nitrous oxide.

The most common journals publishing studies on the impact of COVID-19 on air quality include Science of the Total Environment, Aerosol and Air Quality Research, and Air Quality, Atmosphere & Health

Science of the Total Environment

Science of the Total Environment has published many studies on the impact of COVID-19 on air quality. It is the most active journal in this field, with 203 publications related to COVID-19 and air quality as of 2021. The journal has an impact factor of 10.753 and a citation frequency of 12,176, making it quite influential.

Aerosol and Air Quality Research

Aerosol and Air Quality Research is an independently run, non-profit journal. It has published 125 articles on the impact of COVID-19 on air quality as of 2021. The journal has a 5-year impact factor of 2.5 and a 2023 journal citation report of 2.8.

Air Quality, Atmosphere & Health

Air Quality, Atmosphere & Health has an impact factor of 5.804 and a citation frequency of 1115. It has published 70 articles on the impact of COVID-19 on air quality as of 2021.

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