The cause? A strong weather inversion, one that also helped trap air pollutants closer to the ground, prompting a spike in fine particulate matter (also known as PM2.5). The Liberty-Clairton area appeared several times on the list of areas in the United States with the worst air quality index.
It wasn’t unexpected: The inversion and poor air quality it helped create prompted the Allegheny County Health Department to issue a special public statement warning the public of the health impacts associated with elevated levels of air pollution. The state Department of Environmental Protection sent out its own warnings, declaring Christmas Eve and Christmas Day as Code Orange Air Quality Action Days.
How bad was it? Today makes six days in a row that the Liberty monitor exceeded the 0.005 ppm 24-hour h2s standard. Preliminary data from ACHD also showed an exceedance of the 24-hour average PM2.5 NAAQS limit on Dec. 21, Dec. 22, Dec. 23, Dec. 24 and Dec. 25.
ACHD’s statement about the inversion and heightened levels of air pollutants noted that officials had been “in touch” with major emissions source operator U.S. Steel, saying there was “no unusual activity” at the company’s Clairton Coke Works. The message also indicated that all of the company’s Mon Valley facilities were “operating within their permit limits.”
However, GASP’s Executive Director Rachel Filippini wanted to be sure to put the situation into perspective.
“Temperature inversions are natural weather phenomena that we cannot alter, but we do have the power to reduce the amount of pollution coming from local sources when we know one is taking place or is forecast to take place,” she said. “Given how poor local air quality has been, industry – especially in the Mon Valley – could and should be proactive and take steps to minimize the air pollution to which we are all subjected. And ACHD should do more to ensure these companies act like the good neighbors they claim they want to be.”
She added: “Even operating under normal conditions, U.S. Steel is permitted to emit tons of pollution each year. If the company can operate at a reduced production rate due to market conditions, surely it can be proactive about public health and operate less when stagnant air is predicted.”
UPDATE: On Thursday afternoon ACHD released the following statement from its Deputy Director of Environmental Health Jim Kelly via the county’s Allegheny Alert notification system regarding air quality in the region:
“The Allegheny County Health Department continues to monitor the air quality in our region following several days of heavy fog, very light winds and continued strong and lengthy temperature inversions. The weather resulted in the DEP twice forecasting a Code Orange Air Quality Action Day for PM2.5 on December 24 and 25 for the Liberty-Clairton area.Preliminary data has shown exceedances of the 24-hour federal PM2.5 standard at the Liberty monitor (greater than 35 micrograms per cubic meter) from Saturday, December 21 through Wednesday, December 25. As a result, ACHD’s Air Quality Division has been in daily communication with U.S. Steel and other facilities in the Mon Valley to monitor all activity and ensure compliance with their permits.While air quality is expected to continue to improve in the upcoming days, residents are encouraged to submit air quality complaints by calling 412-687-ACHD (412-687-2243) or using the department’s online form: http://bit.ly/2PQoWLK.”
Editor’s Note: For those who want to take a deeper dive into the monitored data, check out these graphs: