Mon Valley air quality prompts another pollution warning

Unfavorable weather conditions led the Allegheny County Health Department to extend a weekend warning about Mon Valley air quality through at least Tuesday morning.

On Monday morning, the Mon Valley “experienced one of the strongest weather inversions in some time,” the health department said in a countywide email alert. A day earlier, The state Department of Environmental Protection declared a Code Orange Air Quality Action Day for the Liberty-Clairton area for fine particulate matter.

The inversion — defined as cool air near the ground and a mass of warmer air above it, which traps pollutants —had broken by mid-day Monday but air dispersion remained poor throughout the day, leading to stagnant air conditions, according to David Good, program manager of air monitoring and source testing for the health department.

Readings for PM2.5, a measurement of pollutant particles in the air, exceeded federal guidelines at the Liberty monitor near Clairton on Saturday, county statistics show.

The Mon Valley Air Pollution Warning will continue through at least tomorrow morning, October 25. pic.twitter.com/DVBmtwzAlL

— Allegheny County Health Department (@HealthAllegheny) October 24, 2022

U.S. Steel, whose Clairton Coke Works is the largest air pollution source near the Liberty monitor, said it was following guidelines set in the Mon Valley Episode Rule, a measure started in September 2021 to cap air pollution during such weather events.

“During recent inversions, U. S. Steel has been utilizing its internal weather prediction tool and often voluntarily implementing its PM2.5 warning plan actions before ‘watch’ or ‘warning’ phases are issued by the Allegheny County Health Department,” spokesperson Amanda Malkowski told the Tribune-Review. “We have utilized our episode plan agreed on with the ACHD throughout the inversions.”

Not only has pollution exceeded standards for particulate matter, the air in the Mon Valley also has an unfavorable smell, the group Breathe Project said in a prepared statement. More than 1,134 smell reports were logged in the SmellPGH crowd-sourced app in October, and more than 355 smell reports in the last three-and-a-half days.

“Residents in SWPA shouldn’t have to endure having the worst air quality in the country for half the month of October,” said Matt Mehalik, executive director of the Breathe Project. “Why isn’t more being done to enforce rules on the books to prohibit serial polluters from spreading their stinky and health-damaging air across the fence line of their plants into our communities in the Mon Valley and into the City of Pittsburgh?”

The nonprofit Group Against Smog and Pollution (GASP) also chimed in, asking the health department to be vigilant in evaluating how major players did business during the inversion conditions.

“We expect the pollution sources covered by the Mon Valley Episode Rule are doing all that ACHD has demanded of them to reduce emissions,” said Patrick Campbell, GASP’s executive director. “At the same time, we expect ACHD to conduct its own analysis of source emissions, source compliance, air quality, and atmospheric conditions. We can’t say for sure if the rule is working exactly as ACHD hoped, but the department has the tools and obligation to ensure the rule protects public health.”

The county health department warned that young children, the elderly, and those with respiratory problems, such as asthma, emphysema, and bronchitis, are especially vulnerable to the effects of air pollution and should limit outdoor activities during this time.