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Air pollution contains many toxic substances, including chemicals, gases, and particulate matter. Exposure to air pollutants is associated with poor health outcomes and increased risk of disease. Findings from a new study suggest that exposure to air pollutants, especially nitrogen dioxide, increases the risk of death due to COVID-19.

Nitrogen dioxide is a gaseous air pollutant composed of nitrogen and oxygen. Commonly measured in air in terms of parts per billion, nitrogen dioxide is often present in air in urban areas with heavy automobile traffic. Exposure to nitrogen dioxide is associated with increased susceptibility to respiratory infections.

To understand the relationship between exposure to key urban air pollutants (especially PM2.5, nitrogen dioxide, and ozone) and COVID-19 outcome, the authors of the study considered the case-fatality rate and the mortality rate – two major death outcomes associated with COVID-19. The case-fatality rate refers to how many of those with a confirmed diagnosis of COVID-19 die as a result of the disease. The mortality rate refers to the total number of COVID-19 deaths in the population.

They found that exposure to urban air pollutants increased risk of poor outcome in COVID-19 in a dose-dependent manner. For every 4.6 parts per billion increase of nitrogen dioxide in the air, the case-fatality rate increased more than 11 percent and the mortality rate increased more than 16 percent. The authors' analysis also revealed that reducing nitrogen dioxide exposure could have prevented nearly 15,000 deaths among those who tested positive for COVID-19.

These findings suggest that people living in urban areas where air pollution levels are high are at great risk of poor outcomes associated with COVID-19. They also support current efforts to reduce exposure to air pollutants in urban areas in the United States.

Another prominent component of air pollution is benzene. Research indicates that sulforaphane, a phytochemical derived from broccoli sprouts, promotes excretion of benzene. Watch this clip featuring Dr. Jed Fahey to learn more.


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This news story was included in a recent science digest.

