EPA says Maricopa area air too dirty

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The Environmental Protection Agency has designated the city of Maricopa and surrounding areas as non-compliant with the federal PM 2.5 air quality standard.
 
PM 2.5 is a measurement of particles in the air that come from combustibles such as gasoline, coal-fired power plants and other similar sources.
 
The city and surrounding area were first declared non-compliant more than two years ago, but the ruling and creation of a map showing what area would be certified as a non-attainment zone was challenged by Governor Brewer.
 
That challenge was eventually overruled and the EPA issued a PM 2.5 non-attainment map for Pinal County last week.
 
Donald Gabrielson, Pinal County Department of Developmental Services and Air Quality director, said issuance of the map triggers a three-year timeframe in which an inventory of emissions and a plan to reduce those emissions must be completed.
 
However, he said it may not take a lot of work to become compliant with federal standards because PM 2.5 levels have already been reduced in Pinal County.
 
“The data that found this area in non-attainment is three years old,” he said. “The senor in the area that was out of compliance is now below the tolerance level.”
 
The air-quality sensor Gabrielson referred to, known as the Cowtown sensor, is located near the Maricopa-Casa Grande Highway and Murphy Road.
Three years ago when the non-attainment designation process began, the sensor was averaging 48 micrograms per cubic meter a day. Now, due to changes in management practices by cattle feed companies, the meter is averaging 31 micrograms a day or less.
 
The federal threshold level for non-attainment is 35 micrograms.
 
“What we are going to have to do is work to ensure we keep the levels we have had the past couple of years,” Gabrielson said.
 
PM 2.5 is not the only air quality issue affecting the area.
 
The county is currently waiting for a map to define a non-attainment area for larger PM 10 particles.
 
Once this map is received, it will trigger the same process called for in the PM 2.5 area, but with a shorter, 18-month timeframe for completion.
 
Maricopa will almost certainly be included in the PM 10 non-compliance map because of readings at the Cow Town sensor.
The sensor was in violation of the PM10 air quality standard 200 days a year on average at the time the Maricopa area was declared non-compliant. That number has since dropped to 20 days a year, but federal standards only allow one day a year.
 
“To go from 20 violations a year to less than one is going to be a lot less difficult than going from 200 to less than one,” Gabrielson said.