As the world is trying to battle through one of the worst public health emergencies in the history of mankind— the COVID-19 pandemic, there has been one part of the world that has provided positive news in the midst of our pain—the improvement of the global air quality. People across the world are struggling to contain a deadly virus that has radically altered our lives creeping over 5 million confirmed cases, while crippling economies, societies, and have forced people to remain in their homes. With fewer vehicles on the streets and industrial activity halted across the world, air pollution has decreased worldwide.

One study, led by researchers at the Royal Belgium Institute for Space Aeronomy in Brussels, Belgium, in the American Geophysical Union’s journal Geophysical Research Letters, have found that nitrogen dioxide pollution has reduced across the world. They discovered that there has been approximately 40% reduction over China and 20-38% reductions over Western Europe and the United States.

The second study, conducted by Xiaoqin Shi and Guy Brasseur at the Max Planck Institute for Meteorology in Hamburg, Germany, found that there was a 60% decrease in nitrogen dioxide levels and 35% decrease in matter pollution levels in northern China during the lockdown, January 23^rd through February 29^th, 2020. “Such a significant drop in emissions is unprecedented since air quality monitoring from satellites began in the 1990s”, said Jenny Stavrakou, an atmospheric scientist at the Royal Belgian Institute for Space Astronomy in Brussels.

Nitrogen dioxide is a highly reactive gas that is primarily released into the air through the combustion of fuel. Emissions from automobiles, trucks, power plants, and industrial equipment include copious amounts of nitrogen dioxide that collects in the air. According to the EPA, nitrogen dioxide is responsible for air haziness and reduced visibility, added nutrient pollution in coastal waters, and acid rain production that damages ecosystems worldwide. People in areas that are considered highly polluted with nitrogen dioxide suffer from respiratory illnesses due to the pollution because it irritates airways and can aggravate other conditions and lead to infections.

The reduction in nitrogen dioxide has led to an increase in surface ozone levels, another air pollutant. Guy Brasseur, a professional at the National Center for Atmospheric Research in Boulder, Colorado, remarked, “It means that by just reducing the nitrogen dioxide and particles, you won’t solve the ozone problem.” According to NASA, ground level ozone forms when nitrogen oxide gases react with volatile organic compounds in the troposphere, the lower atmosphere, near Earth’s surface. Ozone is harmful to humans, as it can lead to pulmonary or heart disease, so an increase in ozone is a health threat. These air quality improvements have provided a unique opportunity for researchers and officials to understand current emission regulations, and learn how air quality can change in the future if emission regulations evolve post-pandemic.