Long-term exposure to air pollution increases risk of COVID-19

A summary of research published in the European Respiratory Journal

A new study has found a link between exposure to air pollution and the risk of developing severe forms of COVID-19.

What did the study look at?

The study, published in the European Respiratory Journal, looked at the link between long-term exposure to air pollution and the risk of COVID-19 infection.

Researchers followed over 3.7 million Danish residents aged 30 or above. They collected data from March 1 2020 until April 26 2021, using the National COVID-19 Surveillance System.

The study estimated the levels of particulate matter (PM2.5), nitrogen dioxide (NO2), black carbon (BC), and ozone (O3) in the participants’ residential areas in 2019. Researchers then compared whether people got COVID-19 and, if so, if it caused a stay in hospital and whether they died from the infection.

What do the results show?

The researchers found a strong link between air pollution and an increased risk of infection with COVID-19, hospitalisation and death. This was the case specifically for PM2.5 and NO2 – two major types of pollutants. As the level of exposure to these pollutants increased, the risk of COVID-19 also increased. This link was stronger in people with lower education levels and lower income (known as people with lower socio-economic status). It was also stronger in people with existing lung, heart and brain conditions.

The study also found links between black carbon exposure and COVID-19 outcomes. Increases in ozone were found to decrease the risk of severe outcomes from COVID-19.

Why is this important?

This is the largest study published so far looking at air pollution risk and COVID-19. The findings support other studies showing the harmful effects of poor air quality over time.

The study suggests that long-term exposure to air pollution, specifically PM2.5 and NO2, may put people more at risk of severe forms of COVID-19. This is also the first study to find that people with the lowest socio-economic status were more at risk.

The findings show the importance of lowering air pollution levels to lower the risk of COVID-19. This is particularly the case for vulnerable people and those with underlying health conditions.

Read the original research paper:

Title: Long-term exposure to air pollution and risk of SARS-CoV-2 infection and COVID-19 hospitalization or death: Danish nationwide cohort study