Bethlehem grapples with poor air quality

Bethlehem and the larger Lehigh Valley area are grappling with persistent air quality issues that rank among the worst in Pennsylvania, according to the American Lung Association’s “State of the Air” report.

The culprits include diesel exhaust, traffic and geography, said Benjamin Felzer, a Lehigh environmental science professor and vice chair of the Bethlehem Environmental Advisory Council.

While pollution from the region’s industrial past left its mark on the land and water, Felzer said current air quality challenges are largely a result of contemporary pollution sources such as fossil fuel combustion, especially from diesel engines. 

“The pollutants we’re seeing — diesel fuel, nitrogen oxides and particulate matter — are very much a product of the present,” he said. “On top of that, the geography of the Lehigh Valley compounds the issue.”

The Lehigh Valley, nestled between two mountains, has long been known for its picturesque landscapes and rich history. However, Felzer said its bowl-like structure creates conditions that trap pollutants, especially during temperature inversions when the warm air acts like a lid above cooler air, preventing pollutants from dispersing. 

He said low wind speeds and temperature inversions exacerbate air quality problems by trapping pollutants close to the ground where they are inhaled by people.

The Lehigh Valley still earns a mere passing grade of C, according to the American Lung Association’s “State of the Air” report. The region also ranks no. 79 for the worst high-ozone days and 24-hour particle pollution out of 223 metropolitan areas.

That said, air quality has shown improvements since the 1980s and early 2000s, and Felzer said the country as a whole has seen a decrease in ozone pollution since the 1970s and ‘80s.  

“It certainly has gotten better in the Lehigh Valley since the time of Bethlehem Steel,” he said. 

Still, environmental improvements are not experienced uniformly throughout the Lehigh Valley. 

South Bethlehem, with its urban nature and minimal green space, presents unique environmental challenges, Jack Silva, superintendent of the Bethlehem Area School District, said. 

“The largest open green area outside Lehigh University’s campus is the Broughal Middle School football field,” Silva said. “Beyond that, the landscape is dominated by non-permeable concrete surfaces, exacerbating the impacts of air pollution in the community.”

He said in areas with more grass and open spaces, air pollutants settle in the soil, and their effects are mitigated. In a dense, busy neighborhood like South Bethlehem there’s little relief, as the pollution settles above the ground and is more likely to be breathed in by residents. 

Felzer said while the geography of the Lehigh Valley exacerbates air quality issues, it’s not solely responsible. The primary source of the region’s poor air quality remains traffic emissions and fossil fuel combustion. 

Ozone, nitrogen dioxide and particulate matter are the main pollutants linked to respiratory issues, according to the National Library of Medicine. 

Felzer said these pollutants have significant health effects, especially for individuals with asthma.

As a result, the Asthma and Allergy Foundation of America reported the Lehigh Valley to be the most challenging metro region in the U.S. for individuals with asthma to live in 2024. 

The foundation’s report evaluates 100 of the most populous metropolitan areas based on three key factors — estimated asthma prevalence, emergency department visits due to asthma and the crude death rate from asthma. 

Bethlehem resident Alicia Dietrich recalls struggling with severe asthma while growing up in the Lehigh Valley. Dietrich is now the receptionist at the Pennsylvania Department of Environmental Protection. 

For as long as Dietrich can recall, she and her peers have always joked about the infamous Lehigh saying, “Welcome to the Valley,” because the area ironically comes with high allergens and asthma rates.

Growing up, Dietrich said, her brother’s asthma was so severe it led to his disqualification from serving in the Vietnam War in 1964. 

“If he had been somewhere else, where the air is drier or cleaner, he might have been able to serve in the army and manage his asthma better,” she said. 

The Pennsylvania Department of Environmental Protection plays a role in managing and enforcing air quality standards through its permitting processes.

Andy Schweitzer has been a group manager at the department for 31 years. He said the department enforces air quality regulations through permitting and compliance monitoring. 

“We ensure that companies comply with state and federal regulations to control pollution, and we monitor air quality in real-time across the state,” Schweitzer said. 

The Clean Air Act and Pennsylvania’s Air Pollution Control Act provide a framework for regulating emissions, he said. The department’s responsibility is to issue permits for facilities that may emit pollutants, which Schweitzer said ensures the best available technology is used to minimize their environmental impact.

He said the department inspects a variety of facilities, including cement plants, industrial sites and commercial operations involving industrial processes, as these generally emit the main pollutants. 

“In the Lehigh Valley alone, we might have around 500 to 600 permitted facilities,” Schweitzer said. 

The department is primarily focused on regulating sites that release volatile organic compounds, which are chemicals that evaporate into the air from solids or liquids. He said they also pay close attention to large sources of combustion, such as power plants.

“We have to ensure that companies comply with the regulations,” Schweitzer said. “We monitor their activities, and if violations occur, they are subject to civil penalties.”

Despite these efforts, he also said the continued growth of the Lehigh Valley’s industrial sector, especially the rise of warehouses, poses a significant challenge to improving air quality. 

The expansion of warehouses in the Lehigh Valley has become a contentious issue, as each new facility brings more trucks, leading to more diesel emissions.

“One of the biggest sources of pollution in the Lehigh Valley comes from cars, buses and diesel fuel,” Schweitzer said. “Off the top of my head, I’d say it’s probably about 50% of the air pollution.”

Although the department primarily focuses on environmental concerns, he said the work indirectly impacts health by ensuring compliance with regulations.

The department’s approach remains pragmatic and realistic, recognizing the need to balance economic prosperity with environmental sustainability, Schweitzer said. 

“A lot of times people will call us, saying, ‘Just shut them down’ or ‘Shut the company down,’” Schweitzer said. “It doesn’t really work like that, unless there’s some sort of egregious violation.”

While the department has the authority to take action against facilities disregarding regulations, Schweitzer said its goal is not to shut down operations unless companies intentionally fail to comply.

The department’s website includes updated information regarding regulations on diesel emissions on a local, state and national level. 

In Pennsylvania, all heavy-duty diesel engines used on highways, including those in trucks and buses, must comply with emissions standards set by California. This requirement applies to engines from the 2005 model year and beyond. 

Schweitzer said Pennsylvania aims to reduce pollution and improve air quality by adopting California’s stricter environmental regulations. 

Bethlehem is taking small steps, such as introducing bike lanes and promoting public transportation, but Felzer said significant changes are still needed to drive meaningful improvements.

As the conversation to address poor air quality continues, he said systemic changes and individual actions are both important.

“Restricting the number of vehicles per household isn’t feasible in the U.S., but encouraging fuel-efficient vehicles and providing EV charging stations are more practical approaches,” Felzer said. 

For residents, individual actions like installing HEPA air filters in homes can offer some relief during high-pollution days, as they remove nearly all airborne particles, Felzer said. 

He said real change, however, must come from the top. 

“We should and could each do our part to feel better about ourselves and contribute to the environment,” Felzer said. “But, honestly, it’s not going to make a real difference unless we see big action from cities and governments.”