When Greg Jenkins was growing up on 35th Street in West Philadelphia’s Mantua neighborhood in the late 1960s, he remembers playing on the playground at Morton McMichael School, beneath the only tree that cast shade on the block. Nearby, a manufacturing facility often released a mysterious smell, and trains rumbled along the tracks beside Mantua Avenue, he said.
“We never thought, ‘Oh, those trains are actually producing emissions, and those emissions might be impacting this neighborhood,’” said Jenkins, a professor of meteorology and atmospheric science at Penn State University and founder of the nonprofit Community Innovation for Climate Justice. “It was an unknown issue.”
Now, the house where Jenkins grew up is gone. In its place sits an empty lot with a solar-powered air monitor standing among zucchini, sunflowers, tomatoes and hot peppers in Jenkins’ garden. The air monitor measures levels of unhealthy air pollutants that come from cars, trucks, trains and nearby industrial facilities.
It’s part of a network of air monitors Jenkins is setting up in formerly redlined neighborhoods around his childhood home in West Philadelphia and in Harrisburg, where he now lives. The sensors will help Jenkins compare the air pollution in these areas to that of other neighborhoods in the cities and provide residents real-time information they can use to stay safe.
“When people can see what [the air quality] is, they can at least have the choice of saying, ‘I’m going inside,’” he said.
Filling in air monitoring ‘gaps’ in formerly redlined ZIP codes
Jenkins’ parents moved to Philadelphia’s Mantua neighborhood from North and South Carolina in the early 1950s. Less than two decades earlier, the U.S. government’s Home Owners’ Loan Corporation had marked the neighborhood on a map in red — a racist practice known as redlining. These maps, which rated Black neighborhoods as “hazardous” for mortgage lending, were used to deny these areas capital investment.
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Across the country, researchers have found that formerly redlined areas tend to have worse air quality, hotter temperatures, shorter lifespans for residents and higher rates of diseases including asthma. Julian Marshall, a researcher at the University of Washington who has studied the legacy of redlining in modern-day air quality, said these maps reflected segregation and disparities that existed at the time, as well as the location of existing industry. He said racism in urban planning began before the redlining maps were drawn in the late 1930s and continued afterwards, for example, with many highways built through Black and Latino communities.
“Those differences which were present decades ago and which were reinforced by redlining, have carried forward until the present,” Marshall said.
In the area of West Philadelphia where Jenkins is setting up his air monitors between 30th Street Station, the Philadelphia Zoo, Cathedral Cemetery and Penn Alexander School, adult asthma rates in census tracts ranged from 9.3% to 15.6% in 2024, according to an analysis of federal health data by the city’s Office of Sustainability. That’s higher in some places than the citywide average of 11.5% and the national average of 8.6% of adults with asthma that year.
Philadelphia’s Breathe Philly network, launched in February, offers hourly updates on air pollutant levels that can exacerbate asthma and other respiratory issues at 76 locations throughout the city.
Only two of these monitors are located within the area of West Philadelphia where Jenkins is setting up his network. Jenkins said air pollution could spike above the levels measured at these two monitors in small parts of the neighborhood, for example, due to traffic idling near the entrance to the Schuylkill Expressway.
“That’s what we’re filling in,” he said.
Jenkins has installed 15 monitors so far in West Philadelphia at parks and outside of homes and community organizations. Instead of needing to extrapolate between the city’s two Breathe Philly sensors, residents can look to Jenkins’ denser network for a more accurate picture of the air quality on their block, he said.
The monitors measure particulate matter, nitrogen dioxide and ozone, which can cause respiratory symptoms such as coughing and asthma attacks.
“All three — ozone, NO2 and particulate matter — are known to cause irritation to the lungs,” Jenkins said. “And if you are asthmatic, you’re going to feel it.”
Providing real-time information for health decisions
Dante Leonard said he rarely attended school in June while growing up in West Philadelphia’s Belmont neighborhood. Instead, he said, he would spend the end of each school year struggling with asthma symptoms made worse by the warming weather and pollen.
“The last couple of days of school is when all of the fun stuff [is], it’s like the June fair and the fun day … I never seen none of that stuff,” Leonard recalled. “I’m somewhere in a hospital, and I can’t breathe.”
“It’s like drowning without being in water,” he added.
A few years ago, Leonard helped create a garden on Lex Street in the nearby Mill Creek neighborhood. The garden now hosts one of Jenkins’ air monitors.
Leonard hopes data from the monitors can help push for policy change that would result in cleaner air.
“Understanding that some of the factors that are oppressive in the communities that I’m from, and people that look like me are from, have to do with a lot of things that are super easy to fix,” Leonard said.
Jenkins said the air monitoring data, which is available in real time through an app run by JustAir, will also help people make personal decisions to keep their families safe, such as limiting an asthmatic child’s outdoor activities on a poor air quality day.
Another of Jenkins’ air monitors is set up behind the Mantua Civic Association building. Executive Director De’Wayne Drummond said the data will help staff at his organization decide when to move activities inside, as they did in July when wildfire smoke from Canada pushed Philadelphia’s air quality into the “very unhealthy” range during a Youth Ambassador Program session.
“It was dangerous for the youth to come outside, so we kept them inside,” Drummond said. “Without a monitor like that, we wouldn’t know what type of air we’re breathing — is it good air or is it bad air?”
