Past exposure to air pollution increases the risk that an individual will suffer critical illness after contracting COVID-19, according to a report released on April 8 by researchers at Harvard.

In light of this finding, the recent decision of Trump’s Environmental Protection Agency (EPA) to indefinitely suspend environmental rule enforcement is tantamount to gross negligence. And, as waves of the virus come and go, the rule suspension could have consequences for months to come.

The Harvard research has confirmed what scientists had already strongly suspected to be true: Exposure to air pollution exacerbates the worst effects of the virus. Just one unit more of long-term exposure to hazardous fine particulate matter, the researchers found, is correlated with an increase in COVID-19 mortality of 15 percent. Inhaling pollutants like fine particulate matter can weaken the respiratory system and lead to conditions like asthma, which is known to worsen COVID-19 for certain patients. (The study, which has not yet been peer reviewed, has been submitted for publication at the New England Journal of Medicine.)