COVID-19 Policies Impact on Air Quality

Measures Examined in Studies

• Particulate Matter (PM2.5) is tiny particulate matter that can lodge in lungs and cause health problems. The main source of this pollutant in most countries is vehicle emissions.

• Nitrogen Dioxide (NO2) is a gas that is produced when burning fuel. NO2 can cause irritation of the lungs and worsen respiratory disease like asthma.

• Ozone (O3) is three atoms of oxygen. It protects our environment when it is in the upper atmosphere (stratosphere). But when it is at ground-level (troposphere), ozone causes a variety of health problems. Ground-level ozone is the primary ingredient in smog. Ozone is created and destroyed by chemical reactions from other pollutants.

China

The COVID-19 outbreak started in Wuhan, China which is the 9^th largest city in China. A study by Sicard et al. found that NO2 levels in Wuhan were 56.8% lower during lockdown than during the same time during the previous 3 years (Sicard, 2020).

PM2.5 levels reduced during lockdown were 36% greater in Wuhan than South Europe cities in the study (Sicard, 2020). The authors attributed this greater reduction in PM2.5 to the reduced coal use in China. While many countries' primary source of PM2.5 pollution is transportation, a large portion of China’s PM2.5 pollution comes from coal use which was reduced during lockdown and cessation of smelting industries activity (Sicard, 2020). This reduction in coal use was thought to contribute to the greater reduction in PM2.5 in China.

Ground-level ozone levels in Wuhan were 35.1% higher during lockdown than during previous years (Sicard, 2020). Ozone is a secondary pollutant and is influenced by concentrations of primary pollutants. Ozone increase has been attributed to the decreased concentrations of NO resulting in reduced consumption of ozone (Kanniah, 2020). Many other countries, including India, also saw an increase in ozone levels.

India

Particulate matter (PM) is the primary pollutant in India and was estimated to contribute to the premature deaths of about 1 million people in 2015. India launched a plan in 2019 to reduce PM pollution by 30% by 2024 so a portion of the results in India may be attributable to actions taken in this plan (Sharma, 2020).

Lockdown had the biggest impact on small particulate matter, PM2.5, with an average reduction of 43% (Sharma, 2020). India saw a 30% improvement in Air Quality Index during lockdown with improvements varying by region from 15% to 44% (Sharma, 2020).

This video provides more information on the effects of lockdown on India's air pollution.

United States

Lockdown measures in the United States have been less stringent than many other countries and measures varied from state to state.

One study found that states that required early closures of non-essential business had an average reduction of PM2.5 of 11.3 % compared to previous years while counties that did not require early business closures did not have a significant reduction in PM2.5 levels (Berman, 2020). NO2 reduction was also greater in states that required early business closures (26.59% vs 23.72%) (Berman, 2020). Urban counties showed greater reductions in NO2 and PM2.5 than rural counties (Berman, 2020).

An interesting exception to this trend was New York. New York closed all non essential businesses and enacted stay-at-home orders, but there was no significant difference in PM2.5 or NO2 (Zangari, 2020). The researchers suggest that travel did not reduce enough in New York during lockdowns to improve air quality measures.

Looking to the Future

Improving air pollution has the potential to save up to 7 million lives each year. The changes in air pollution during lockdowns show us that dramatically improving air pollution by changing our behavior is possible. Many of these studies attributed the improvement to reduced transportation use and industrial coal use. Poor communities are more likely to be near high traffic and industrial areas. These communities tend to have the worst air quality and thus also have the most to gain from reducing air pollution.

Some measures we could utilize to improve air pollution include;

• Increase the number of people working from home

• Maximize distance learning opportunities

• Community investment in mass transit systems

• Reduced coal use

• Reduce industrial air pollution