A recent report, outlined by CNN Business, confirms that air quality indeed improved around the world over the course of 2020 due to the worldwide pandemic lockdowns, with the exception of North America, due to its wildfires. The report, from air purifier technology company IQAir, found that 65 percent of cities globally experienced better air quality in 2020 compared to the previous year, and 84 percent of countries reported overall improvements.

The report echoes previous findings that, because people were not driving or going out, air pollution improved last year. A peer reviewed scientific study from last November, for example, found that statistically significant NO2 (nitrogen dioxide) declines were observed during the current COVID-19 period compared to historical data as well as a 25.5 percent reduction in fine particulate matter. PM2.5—a microscopic pollutant that can cause serious health risks—also showed decreases during the COVID-19 period. The reduction is statistically significant in urban counties and counties from states instituting early non-essential business closures. 

At the same time, according to Bloomberg, North American wildfires, which torched 4.3 million acres last year, made the region the only large area where air quality was actually worse compared to 2019. The report said that 38 percent of cities had fine particulate matter levels exceeding the World Health Organization's air quality standards, up from 21 percent the previous year; the report also noted that 77 of the world 100 most polluted cities were in the United States. Outside of the United States, individual cities, such as Melbourne and Sao Paulo, both of which were close to major wildfires in 2020, also experienced worse pollution in 2020 than in 2019.