Key Points

• Poor air quality has been linked to increases in COVID-19 death rates
• Trees have been shown to materially improve air quality; a significant correlation between NatureScores® and the Air Quality Index by monitor location has also been observed

Connecting Nature, Air Quality and Covid-19

A connection has been repeatedly observed between the spread and case severity of COVID-19 and air pollution. In particular, researchers believe that atmospheric particulate matter (PM) could provide a transporting mechanism that allows the virus to travel greater air-borne distances. Moreover, PM induces inflammation in lung cells, and exposure to PM could increase the susceptibility and severity of a COVID-19 patient’s symptoms. The new coronavirus has been shown to trigger an inflammatory storm that is sustained in instances of pre-exposure to polluting agents.

Long-term exposure to air pollution has also been linked to an increased risk of dying from COVID-19.Now, for the first time, a study has estimated the proportion of deaths from the coronavirus that could be attributed to the exacerbating effects of air pollution in every country in the world. The study, published in Cardiovascular Research, estimated that about 15% of COVID-19 deaths worldwide could be attributed to long-term exposure to air pollution.

The researchers used epidemiological data from previous studies, conducted in the U.S. and China, of air pollution and COVID-19 as well as the 2003 SARS outbreak, supported by additional data from Italy. They combined this with satellite data showing global exposure to polluting fine particles known as “particulate matter” to calculate the fraction of coronavirus deaths that could be attributable to long-term exposure to PM. The results are based on epidemiological data collected up the third week in June 2020; the researchers say a comprehensive evaluation will need to occur after the pandemic has subsided.

In their paper, the authors conclude that air pollution has worsened the pandemic: “Our results suggest the potential for substantial benefits from reducing air pollution exposure . . . The pandemic ends with the vaccination of the population or with herd immunity through extensive infection of the population. However, there are no vaccines against poor air quality.”

One powerful way to combat many forms of air pollution, including high levels of particulate matter, is planting trees. As noted earlier, nature is one of the most cost effective and permanent ways to filter air.

Every year, the percentage of people living in cities rises; at present, over 80% of people in the U.S. live in urban areas. Given their concentrated populations, cities usually are short on green space. However, greenery has been working its way back into urban landscapes, and for many good reasons. In addition to offering aesthetic benefits and increasing property values, trees help make city air safer. Numerous studies have found that, in many cases, nature-based solutions to air pollution might be more effective and cheaper than technology at combating air pollution. Adding plants and trees to the landscapes near factories and other pollution sources could reduce air pollution by an average of over 25%. Proximity to nature also increases longevity; recent studies have concluded that a decrease in air pollution might be one mechanism by which greenness can protect health.

A significant inverse relationship has been observed between NatureScores® and the Air Quality Index by monitor location: a higher NatureScore® predicts better air quality. Furthermore, an inverse relationship between COVID-19 Cases Per Capita by U.S. county (adjusted R-Square of .14 as of January 6, 2021) and COVID-19 Death Rate Per Case against NatureScores® were also statistically significant (adjusted R-Square of .09 on of January 6, 2021). While much more research is needed, this much is already clear: there is a triangular connection among air quality, nature, and the risk of transmission/mortality from airborne diseases.