The U.S. Environmental Protection Agency announced it would keep nearly decade-old particulate matter standards instead of adopting tighter regulations, despite multiple studies linking the pollution to increased COVID-19 death risk.

EPA Administrator Andrew Wheeler said the decision to keep the Obama-era 2012 National Ambient Air Quality Standards for particulate matter was based on a five-year review that included consultation with the agency’s scientific advisors, consideration of 60,000 public comments and feedback received during five public meetings.

But Wheeler said the review that led to the decision did not include any of the research released this year. That includes various research articles from scientists around the world linking exposure to particulate matter pollution and an increased severity of COVID-19 health outcomes, including death.

“Those articles did not come out in time for this five-year review process, but they will be included in the next five-year review process,” Wheeler said.

A Harvard University study in April collected data from 3,000 counties in the U.S., including all 92 Indiana counties, and found that a small increase in long-term exposure to fine particulate matter, also known as PM2.5, led to a large increase in the COVID-19 death rate.

Marion and Lake Counties, the state’s most populous counties, have some of the highest monitored PM2.5 pollution in the state. The counties also have the most COVID-19 deaths in the state.

Researchers from China, Italy, Taiwan, Belgium and other nations found similar links in their own studies.

None of the articles were included in the review, but the EPA knew for at least a decade that both short- and long-term exposure to fine particulate matter pollution caused or was likely to cause a series of negative health effects in humans.

The EPA’s Integrated Science Assessment for Particulate Matter, written in 2019 and released January 2020, noted that evidence existed that fine particulate pollution exposure caused cardiovascular effects like reduced vascular function, changes in blood pressure, systemic inflammation and other effects that led to increased hospital admissions.

The EPA’s researchers also found that exposure to fine particulate matter pollution was likely to cause respiratory effects like aggravated asthma, decreases in lung function, respiratory infection and more hospital admissions.

PM2.5 was also found to likely cause cancer, and it was linked to death through cardiovascular and respiratory effects.

Despite those known risks, Wheeler pointed to decreases in particulate matter pollution as a rationale for keeping the old standards.

“As a result of Clean Air Act programs, and efforts by state, local and tribal governments, average annual PM 2.5 concentrations in the United States fell by 43% between 2000 and 2019. Average PM10 concentrations fell by 46% during the same period,” Wheeler said. “The US now has some of the lowest fine particulate matter levels in the world.”

There are no counties in the state that do not meet the 2012 standards.

Air monitors overseen by the Indiana Department of Environmental Management point to an overall decrease in PM2.5 pollution across the state between 2019 and 2020.

Increases were found in eight counties, most of which contain the state’s highest minority populations.

The largest increases were in South Bend and Indianapolis.

Critics of Wheeler’s move said the decision will have fatal consequences.

“My grandmother always told me that when you know better, you should do better. The science shares with us that 100,000 people are dying prematurely from air pollution in our country and disproportionately it’s African American, LatinX, Indigenous and lower wealth white communities who are being impacted,” said former associate administrator for EPA’s Office of Environmental Justice Mustafa Santiago Ali. “For the Trump administration to make this decision with the information that more folks will die without proactive steps and in a Covid-19 moment which feeds on the chronic medical conditions that comes from exposures to toxic air pollution, shows a disconnect and lack of concern for the lives of citizens that will get sick and die. Trump’s EPA knew better -- they should have done better.”