Pittsburghers have been driving less during the pandemic. Why isn’t air pollution going down? | News | Pittsburgh | Pittsburgh City Paper

Pittsburghers have been driving less during the pandemic. Why isn’t air pollution going down?

click to enlarge CP PHOTO: LISA CUNNINGHAM
CP photo: Lisa Cunningham

Air pollution has dogged Pittsburgh for decades. The city has a history of steel and coal plant emissions, and a ranking of 8th-worst in the country for year-round particle pollution and 16th for short-term particle pollution in this year’s American Lung Association’s State of the Air report. Allegheny County received an F-rating overall from the American Lung Association for its annual number of “high ozone” days and “high particle” days when pollution is at its highest. In short, the issue has long hovered over Pittsburghers’ heads.

You would think, then, that with a drastic decrease in movement, activity, and business on the human end due to COVID-19 quarantine measures, air quality would be improving across the board in the Pittsburgh area. That’s not exactly the case.

A recent analysis by Pittsburgh environmental watchdog Group Against Smog and Pollution (GASP) found that since quarantine measures took effect in March, particulate matter concentrations are about 23% lower at a monitor in Liberty and 13% lower at the Parkway East air quality monitors. However, another monitor in Avalon saw little to no change over the past few months. According to GASP, hydrogen sulfide pollution also exceeded state standards twice in the month of May. 

An analysis by NPR also found that while the quarantine has seen some improvements in air quality overall, ozone levels have only dropped in Pittsburgh by about 9%. The NPR report cites the continued operation of coal-fired power plants and coking plants as driving pollution.

“We know that a significant amount of our pollution comes from industrial sources — combustion of coal, whether from coal-fired power plants or coke making,” says Rachel Filippini, executive director of GASP. “That is going to have to be an area that cleans up in order for our region to really have cleaner air.”

Matt Mehalik, executive director of Pittsburgh air quality information clearinghouse Breathe Project, says that multiple types of pollution impact air quality. While monitors have seen a drop in carbon monoxide pollution from cars, PM 2.5 fine particles (tiny particles or droplets in the air that are less than 2.5 microns in diameter, or smaller than the period on this sentence) emitted primarily by industrial plants and diesel trucks have not dropped to as significant a degree. 

“[This year] seems to be trending lower [for particles], but it’s not lower than what we’ve seen in past years throughout March, April, and May, which tend to be the months that our region experiences the lowest levels of pollution anyhow,” Mehalik says. “What that means is, you cannot say definitively that the reductions in pollution can be explained solely by any sort of reduction in activity associated with COVID-19 — they could be explained by weather variation as well.”

Mehalik predicts that we will have a better sense of how quarantine measures are affecting pollution if they last for a longer period of time, giving scientists a larger sample size to study.

“Our confidence in what we know will go up as time goes on,” he says. “We just have to keep collecting data and doing these analyses and comparisons.”

Measuring air pollution relies on a number of factors, like weather and location, says John Graham, senior scientist at the Clean Air Task Force. Graham studies air pollution in the Western Pennsylvania region, looking at county data to pinpoint pollution hotspots.

“It depends where you are looking in the county,” says Graham. “So, if you’re looking on a road, or next to a road, you are going to expect to see those changes more easily than if you are looking at measurements in a residential neighborhood.”

In the long term, Graham says, Pittsburgh has made a lot of progress, but there are still issues.

“If you were to compare air pollution in the U.S. to air pollution 20 years ago, it’s — well, I don’t want to say night and day, but it’s a really big change in a positive way,” says Graham. “But what has remained is that Pittsburgh was toward the bottom of the barrel years ago. And even though it’s made all these great strides, other places have also made those great strides.”

Graham also cites the industrial footprint in western PA as a major source of particle pollution, in the short and long term. While car usage has gone down during the pandemic, cars only contribute about 5-10% to particle pollution in western PA, so a reduction in driving isn’t likely to make much of a dent in particle levels.

Air quality can have an impact on everyday life and health, exacerbating asthma, respiratory and cardiac diseases, and increasing risks of cardiovascular diseases and cancers. One way Pittsburghers can get involved in monitoring pollution is through the Carnegie Mellon University’s CREATE Lab Smell PGH app, which lets users log odor incidents in their area to send to the Allegheny County Health Department. 

Beatrice Dias, co-director of outreach at the CREATE Lab, says that reports of odor incidents have been down over the past few months of quarantine, but that a spike in reports occurred over this past Memorial Day weekend. However, Dias says the decline might also be attributed to people who normally leave home for work staying indoors, where outdoor pollution smells can be less obvious.

“The app is [currently] not the best indicator of what the air quality is," says Dias, who notes that typically the Smell PGH app correlates with poor air quality in the region, but since less people are outside due to the COVID-19 pandemic, there are fewer smell reports, which doesn't mean the air quality is actually improving. "It's more how people are engaging with the app and how people are functioning in everyday life. Most of the reports come in, usually, in the morning, and a lot of those people are reporting every time they go outside to go to work.”

Filippini expects that as more of the state enters the “green” phase of restrictions, emissions may begin to rise further again. Despite this, she feels that now may be a time to focus on sustainable steps forward, citing the concept of “#HealthyRecovery” brought up in a letter sent to G20 leaders by a coalition of 350 international health professional groups earlier this month.

“This is a terrible thing that has happened to the world, and so many people have lost their lives,” says Filippini. “But what kind of positive can come out of this? What can we learn from this experience about our relationship with nature, our relationship with energy, and our relationship with justice issues?”

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