A global health crisis isn’t exactly known for its silver linings.

But here’s a small respite from all the bad news and lifestyle disruptions caused by the coronavirus outbreak: New Jersey’s air quality is the cleanest it’s been in years.

Less fuel is being burned and that means less pollution in the air as millions of Garden State residents stay inside, keep their cars in the driveway and work remotely — or not at all.

“It’s basically the effect of shutting down our economy," said Monica Mazurek, the resident air quality expert at the Rutgers Center for Advanced Infrastructure and Transportation. "Everything that we’d normally do that requires energy production is vastly attenuated.

“This is a short-term effect," she added. "As long as our economy is shut down, we’re going to see better air quality.”

The bad stuff we breathe

There are multiple kinds of air pollution; the U.S. Environmental Protection Agency sets standards for six different pollutants. One of those is particulate matter, or soot, which is created when combustible materials like diesel, gasoline, coal or wood are burned.

When people breathe in particle pollution, the microscopic material can become embedded in their lungs and possibly enter their bloodstream. The pollution is linked to heart and lung problems, according to the EPA, including premature death in people with heart or lung disease, irregular heartbeat and decreased lung function.

Diesel engines, Mazurek said, are the largest source of particulate matter pollution in New Jersey. Now fewer vehicles are traveling Garden State roads and particulate matter levels were lower across the New Jersey this past March than they were in March 2019.

Mazurek said New Jersey’s air quality in recent weeks is reminiscent of the days following 9/11, when the New York City metro area was locked down after the terrorist attack.

There’s a bit of irony here; the improved air quality is driven by a virus that attacks its victims’ ability to breathe. Unfortunately, the suddenly cleaner air may have come too late to help reduce the threat that the virus poses to at-risk populations. Low air quality in cities like New York and Chicago has been linked to higher COVID-19 death rate, according to a new Harvard study.

The difference between March 2020 and March 2019 are most pronounced in places that typically see heavy vehicle traffic. An air quality monitoring station in Elizabeth, for example, showed that nearly every day of this past March had lower particulate matter levels than the same day in 2019. That station is at the New Jersey Turnpike toll plaza for Exit 13, near the Phillips 66 Bayway Refinery.

A similar situation played out in Jersey City, where particulate matter is measured by an air quality monitoring station at a Jersey City Fire Department station on Newark Avenue, near I-78.

Another pollutant that has dropped from New Jersey’s air in recent weeks is nitrogen dioxide (NO2), which is a key ingredient to the formation of low-level ozone, also known as smog.

Smog forms when tailpipe emissions combine with other elements on warm, sunny days. When breathed in, smog attacks a person’s respiratory system — some have described it as “sunburn for the lungs.”

Satellite imagery provided to NJ Advance Media by Descartes Labs shows that NO2 levels in Garden State air have were significantly lower this past March when compared to March 2019.

New Jersey isn’t alone in this trend. Dramatic drops in NO2 have been measured by satellites in other virus hotspots like China and Italy. Philadelphia, which not been hit as hard as other American cities but is very much locked down through social distancing measures, has seen a dip in NO2 levels as well, according to WHYY.

What happens next

This boost in air quality is almost certainly temporary. Once the coronavirus pandemic passes, and society returns to normal, New Jersey’s highways will again be flooded with traffic.

Experts expect that once businesses reopen and the economy begins to recover, pollution will return to normal levels, according to the Los Angeles Times.

For long-term air quality improvement, Mazurek said the most important thing that can be done is to reduce the amount of emissions for cars, trucks and other vehicles.

That’s why Mazurek is particularly concerned that President Donald Trump’s administration has rolled back strict, Obama-era gas mileage standards which would force car manufacturers to build more efficient vehicles.

Last week, the EPA finalized a new rule that requires car manufacturers to improve the average gas mileage of cars and trucks sold in the U.S. by 1.5% each year between model year 2021 and 2026. That’s less strict that a rule issued under President Barack Obama, which called for 5% improvements each year. The government’s own estimates predict that these looser rules will lead to more deaths from air pollution in America, according to the Washington Post.

“If we want to have cleaner air quality down the road, we need to improve fuel efficiency,” Mazurek said.

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Michael Sol Warren may be reached at mwarren@njadvancemedia.com. Follow him on Twitter @MSolDub. Find NJ.com on Facebook.

J. Dale Shoemaker is a reporter on the data & investigations team. He can be reached at jshoemaker@njadvancemedia.com. Follow him on Twitter at @JDale_Shoemaker.

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