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Allegheny County Experiences Two Air Quality Exceedances Aug. 9; Air Quality Action Day Again Declar

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This past weekend of warm and muggy weather was punctuated by two air quality exceedances, according to initial data from the Allegheny County Health Department (ACHD). 

Concentrations of hydrogen sulfide (H2S) were bad enough at the Liberty air quality monitor the morning of Sunday, Aug. 9 that by 10 a.m. it was mathematically impossible to stay below Pennsylvania’s 24-hour standard. The average concentration of H2S at the Liberty monitor Sunday was 0.008 ppm. The standard is 0.005 ppm.

Although many monitoring sites throughout southwestern Pennsylvania showed elevated levels of ozone, the average concentration at the South Fayette air quality monitor from noon to 8 p.m. Sunday was 0.071 ppm, exceeding the federal standard for the maximum eight-hour average. 

The state Department of Environmental Protection (DEP) declared both Sunday and today, Aug. 10 as Air Quality Action Days for ozone.

Air Quality Action days are issued when the air quality index (AQI) is forecast to be in the orange (unhealthy for sensitive populations) range or higher. On Air Quality Action Days, young children, the elderly, and people with respiratory problems like asthma or emphysema are especially vulnerable to the effects of air pollution and should limit outdoor activities.

Residents and businesses within the Air Quality Action Day area are strongly encouraged to voluntarily help reduce air pollution by: 

  1. Conserving electricity by setting the air conditioning to a higher temperature;

  2. Combining errands to reduce vehicle trips; 

  3. Limiting engine idling; and 

  4. Refueling cars and trucks after dusk.

GASP encourages everyone to be a good neighbor and forego fires, which are prohibited on Allegheny County on Air Quality Action days.

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