The Ben Franklin bridge connecting Philadelphia, Pa., to Camden, N.J., in a haze of smoke from Canadian wildfires on June 7, 2023. (Kimberly Paynter/WHYY)

Philadelphia experienced its worst air quality since 2008 this week, thanks to the smoke wafting down from Canada. Even more worrying: the measurement is part of a downward trend.

We’d been doing so well. For the first time ever in 2018, Philadelphia experienced over 200 days with good air quality, up from 1980’s low of 31 good air days. Over the next few years, the count continued to increase — until 2021, when it dropped back down. Last year’s air quality improved slightly, but so far this year, Philly has experienced a fairly even split of good and compromised air quality days. It’s quite possible we could dip once again.

The sources that impact air pollution in Southeastern Pennsylvania can vary significantly. They include wildfires exacerbated by climate change, like this week’s surprisingly disruptive haze. The region is also exposed to large amounts of air pollution from local industry, heating and cooling, and transportation, as well as the industrial and mobile pollution that migrates from the western half of the state. 

Then there’s the factor of the wind, which travels here from Southwest Pa. in the summer and from Northwest Pa. in the winter. When it reaches this region, it swirls and gets trapped as it blends with local air pollution.  

Air pollution is also impacted by heat. Philadelphia’s first days of 2023 with elevated ozone pollution directly corresponded to an unexpected heat wave that included three consecutive mid-April days over 80°F. When volatile organic compounds (VOC) and nitrogen oxides (NOx) react with heat in the atmosphere, they create dangerous ground-level ozone, the main constituent of smog. Greenhouse gas affects your local air pollution.  

But there are several initiatives in the works that can help ensure Philly’s progress over the past decades isn’t reversed. They come at the federal, state, and hyperlocal levels. 

Pennsylvania is poised to enter into the Regional Greenhouse Gas Initiative (RGGI), a cap-and-trade program intended to reduce carbon pollution from power plants while generating an estimated $600 million for the commonwealth. 

The U.S. Environmental Protection Agency, meanwhile, is considering a new series of standards including more stringent carbon dioxide limits for power plants, updated vehicle emission requirements, and updated caps for particulate matter 2.5 (also known as soot). 

Then there are the EPA’s proposed rules to decrease methane emissions and other air toxics created during extraction of oil and natural gas, including fracking. They would require all wells to be regularly inspected for repairs, and require the use of “no bleed” pneumatic devices that don’t vent gas to the atmosphere. Reducing venting is vital to air quality because fracked gas contains methane, VOCs, and other known carcinogens like benzene. Unfortunately, the draft rule still contains exceptions for venting and flaring gas (Pennsylvania extracts the most gas of any state in the country besides Texas). 

Philadelphia Gas Works, the largest public gas utility in the country, is already experimenting with electric and air-driven “no bleed” pneumatic devices that control pressure without venting gas to the atmosphere. PGW is spending $532,000 this year to install “zero emission controllers” at its pressure control stations throughout the city, as well as its large storage facilities in Port Richmond and South Philly. 

Philly residents can also help! Seek out ways to increase energy efficiency at your home, adopt heating and cooling powered by renewable energy, and use more sustainable forms of transportation, including electric vehicles, which are increasingly available and affordable. 

We need all of these efforts to improve air quality and avoid a slide back to the dark days of polluted skies over Philadelphia.

Russell Zerbo has been an advocate at the Clean Air Council since 2012. He helps residents in Pennsylvania, Delaware, and New Jersey communicate with government regarding environmental issues. He has a...