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County Sees More Air Quality Exceedances Monday, Tuesday Designated as Code Orange Air Quality Actio

Air quality stayed mostly in the unhealthy range Monday, with concentrations of fine particle pollution exceeding the federal health-based standard at all three of Allegheny County Health Department’s operating PM2.5 monitors.

The 24-hour average PM2.5 National Ambient Air Quality Standard is 35 micrograms per cubic meter. Yesterday the 24-hour average at the Lawrenceville Monitor was 36.6 ug/m3, 44.5 ug/m3 at Liberty, and 59.1 ug/m3 at Parkway East. ACHD’s Avalon monitor, which also monitors PM2.5, was offline.

That brings the unofficial PM2.5 exceedance tally for 2021 to three at Liberty. The first two exceedances occurred on March 10 (44.6 ug/m3) and April 7 (38.2 ug/m3), according to preliminary data. ACHD’s final, official data reported to EPA could differ.

“This latest bout of bad air again reinforces the need for strong episodic weather regulations,” GASP Executive Director Rachel Filippini said. “Businesses need to do their part and reduce emissions-causing activities on days when air quality is expected to be poor in part because of weather conditions. Residents need information on how to mitigate their exposure to harmful air pollutants. The proposed regulation would help accomplish both of these things.”


Unfortunately, PM2.5 wasn’t the only air pollutant of concern Monday: There was also another exceedance of Pennsylvania’s 24-hour average for hydrogen sulfide (H2S) at the Liberty monitor – bringing 2021’s total to 30.

The day culminated in the state Department of Environmental Protection designating today, Tuesday July 6 as a Code Orange Air Quality Action Day for ozone in not only Allegheny County but also, Armstrong, Beaver, Butler, Fayette, Washington, and Westmoreland.

On an Air Quality Action Day, 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.

GASP joins DEP and the Allegheny County Health Department in encouraging residents and businesses to voluntarily help reduce air pollution by: 

  1. Driving less by carpooling or using public transportation; 

  2. Combining errands to reduce vehicle trips; 

  3. Limiting engine idling; 

  4. Refueling cars and trucks after dusk; and 

  5. Conserving electricity by setting air conditioning to a higher temperature and turning off lights that are not in use

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