Shaun McKinnon
Arizona Republic
Lots of folks walked outside Christmas morning and found the air filled with the aroma of a holiday fire, but that was not the plan, not according to air quality managers who asked residents to find other ways of stoking cheer.
Maricopa County’s air monitors exceeded federal pollution standards both Christmas Eve and Christmas Day, even after the county posted no-burn restrictions for both days in an attempt to keep the air clean. At some locations, pollution levels were more than twice the federal health standard.
The photo at right was taken Christmas morning looking toward South Mountain in Central Phoenix and shows the layer of haze that had developed.
Although skies were relatively clear Friday, the haze built quickly and remained visible much of Monday and even into Tuesday morning.
Because the air quality declined so quickly, officials say wood-burning fireplaces were likely a primary cause of the pollution. Fireplaces produce fine dust and soot particles, known as PM2.5 because they are 2.5 micrometers or smaller in diameter.
Such small particles can find their way into the lungs, the bloodstream and even to the heart, where they can clog airways and arteries and worsen existing breathing problems. Children with asthma and adults with respiratory ailments can become ill quickly when fine dust levels rise.
Monitors posted high readings both Saturday and Sunday. The highest was at the West Phoenix monitor, near 39th Avenue and Earll Drive, where the 24-hour average concentration of PM2.5 pollution was 67.4 micrograms per cubic meter on Christmas Day.
The EPA health standard for PM2.5 is 35 micrograms per cubic meter.
The same monitor also exceeded the health standard on Saturday with 45.2 micrograms per cubic meter.
Monitors near Central Avenue and Broadway Road (51.9 on Saturday, spiking to 60.9 on Sunday) and 27th Avenue and Durango Street (49.2 on Sunday) also exceeded the standard for the weekend. An exceedance at one monitor means the entire region is out of compliance for the period.
Air quality will improve through the week, according to the Arizona Department of Environmental Quality, but officials worry that it could degrade again next weekend when people begin to light fires for the New Year’s holiday.
The county has exceeded health standards on New Year’s Eve and New Year’s Day frequently in recent years, including 2011. It’s possible the county will impose no-burn day rules again for the weekend.
