As the Trump administration relaxes several environmental regulations governing air pollution, scientists have learned that a person’s long-term exposure to microscopic air emissions — including those from power plants, wood pellet facilities, and quarries — is a risk factor for dying from COVID-19.
Harvard University researchers analyzed 17 years’ worth of data for 3,000 US counties, comprising 98% of the population, through April 4. The study concluded that even a small increase in long-term exposure to a type of pollutant known as PM2.5 “leads to a large increase in COVID-19 death rate — 20 times that observed for PM2.5 and mortality from all causes.”
PM2.5 is shorthand for invisible solid and liquid particles that are smaller than 2.5 microns; for comparison, a human hair is 30 microns.
Since PM2.5 is so tiny, it easily burrows deep into the lungs, where it can cause or contribute to premature death in people with heart or lung disease, non-fatal heart attacks, irregular heartbeats, aggravated asthma, decreased lung function, and increased respiratory symptoms such as inflammation, airway irritations, coughing, or difficulty breathing
Because PM2.5 exposure can weaken heart and lung function, it can also increase the severity of COVID-19 symptoms and the risk of death.
As of April 14, North Carolina has reported nearly 5,000 positive cases of COVID-19, 108 deaths and 333 current hospitalizations. However, because of testing limitations, those figures are an undercount.
The findings were consistent, even after researchers adjusted for population size, hospital beds, number of individuals tested, weather, and socioeconomic and behavioral variables including obesity and smoking.
“The study results underscore the importance of continuing to enforce existing air pollution regulations to protect human health both during and after the COVID-19 crisis,” the researchers concluded.
On March 26, the EPA announced it would relax monitoring requirements on industry because of the pandemic. Also in March, the Trump administration rolled back fuel efficiency standards for vehicles, which will result in more air pollution. During a media call, EPA Administrator Andrew Wheeler said “benefits” of the weaker fuel efficiency standards “outweigh the costs,” because cars would be cheaper without additional emissions controls.
PM2.5 emissions in the ambient air are measured by their density and in micrograms per cubic meter. A cubic meter is the size of a box that is 3.5 feet high, wide and deep.
The EPA’s legal limit for PM2.5 emissions in ambient air is 12 mcg per cubic meter annually, and averaged over three years.
Daily averages, calculated over the same three-year period, can’t exceed 35 mcg per cubic meter.
In North Carolina, the 16 counties that monitor for PM2.5 in ambient air have not exceeded those thresholds since at 2013, according to state environmental data. (See tables below.)
However, even legal amounts of PM2.5 can contribute to the COVID-19 death rate. The Harvard researchers found that for all 3,000-plus counties in the US, the annual average micrograms per cubic meter was 8.4 to 9.5, well below the 12 set by the EPA.
And even an increase of 1 mcg/cubic meter, researchers found, is associated with a 15% increase in the COVID-19 death rate.
Nonetheless, the EPA announced today it would not change its legal limits.
In North Carolina, about a quarter of the 16 reporting counties had levels above 8.4 mcg per cubic meter, from 2015-2018, according to state data: Catawba, Davidson, Durham, Mecklenburg and Wake.
From 2013-2015, when there were more monitoring stations, 11 of 24 counties reported levels above 8.4 mcg/cubic meter: Catawba, Cumberland, Davidson, Forsyth, Guilford, McDowell, Mecklenburg, Wake and Wayne.
Nor is the state’s data comprehensive. For example, the EPA doesn’t require metropolitan statistical areas with fewer than 1 million people to monitor for PM2.5 air near roads.
Yet even heavily traveled areas can be exempt. The state’s Division of Air Quality doesn’t monitor for PM2.5 in the Burlington MSA, even though Interstate 85 runs through it. The division shut down that area’s PM2.5 monitor in 2015 because the EPA no longer required it.
And since the EPA thresholds are based on averages, these limits don’t account for hotspots. In neighborhoods near industrial pollution sources, often communities of color, levels could be higher.
Industries are required to limit — but not eliminate — their PM2.5 emissions. For example, a state Division of Air Quality study of air near the Enviva wood pellets plant in Richmond County, near Hamlet, showed that industrial and traffic sources, and to a lesser extent, wildfires, emitted 746 tons of PM2.5 in 2014. The Enviva plant was projected to emit another 39 tons.
Statewide, in 2014, all reported sources of PM2.5 emitted nearly 80,000 tons into the air. These sources include the remaining few coal-fired power plants, wood pellet facilities, quarries, concrete plants, (many of which have been exempt from reporting since 2016, when new state rules were adopted), trains, cars and wildfires, including prescribed burns.
The table below shows the levels of PM2.5 in the ambient air, by reporting county. The units are in micrograms per cubic meter.
The EPA’s threshold for the three-year, annual weighted mean is 12 mcg/cubic meter; for the 98th percentile, it is 35 mcg/cubic meter. Asterisks indicate that the county was not required to report that year. Source: NC DEQ’s Division of Air Quality
|County||Average 3-year, annual weighted mean, 2016-2018||Average 3-year 98th percentile, 2016-2018||Average 3-year, annual weighted mean, 2015-2017||Average 3-year |
98th percentile, 2015-2017
|Average 3-year, annual weighted mean, 2013-2015||Average 3-year 98th percentile, 2013-2015|