Brown Cloud Over The Valley Signifies Greater Air Quality Problems

November 22, 2013

You may have noticed a brown cloud hanging over the Valley recently. That is not a metaphor, but it is a visible sign of some of the problems the region has with air quality.

Officials say the cloud is mostly a combination of vehicle emissions and fine particulate matter, known as PM 2.5, that generally comes from burning wood, and they say it is worse this time of year, as temperatures drop and residents use their fireplaces.

"Maricopa County is going to be launching out with a program, it’s a big outreach program to the public, asking them not to burn wood on no-burn days," said Lindy Bauer, the environmental director for the Maricopa Association of Governments which serves as the air quality planning agency for the region.

"During the holiday season, the monitor readings can go up. We do not want that to cause this region to go over the standard," said Bauer.

The standard is set by the federal Environmental Protection Agency. There is also one for coarse particulate matter or PM 10. That is most often associated with dust that gets kicked up into the air from construction, driving on unpaved roads or any number of other activities.

Ira Domsky is a planning consultant with the Maricopa County Air Quality Department and said while the Valley does still have some challenges, in some respects, its air is cleaner than it was several years ago.

"We’re on the verge of some good news for the coarse particulate matter, dust. We’re kind of flirting with violating the standard for smoke and fine particulates," Domsky said.

Officials are hopeful the county’s effort to stop people from burning wood on no-burn days will help. It is expected to be rolled out next month. Sandy Bahr, director of the Sierra Club’s Grand Canyon chapter, said it could, although she also said rules and enforcement are needed.

"If your neighbor’s child has asthma, the child could end up in the emergency room that night, and I think when people understand that, they’re more willing to step up and say, ‘No, I don’t need a fire in my fireplace,'" Bahr said.

There are eight monitors around the county that check fine particulate levels. Any one that exceeds the standard could put the region into non-attainment.

Bahr described the Valley’s air as unhealthful, and said even reaching attainment levels for dust may not be as significant as it seems. That is because there are allowances for what are called “exceptional events,” like dust storms. The EPA has accepted 131 of those exceptional events.

"So you’re going to violate or exceed the particulate standard during that time, but how many of those and how often and how big and for how long? Is it still an exceptional event if you see exceedences five days afterwards?" Bahr asked.

Bahr acknowledged the desert climate can lead to more dusty air, but she said there are ways to mitigate that like not bulldozing areas until they are ready for construction. And, Bahr said Arizonans’ lungs are still affected by coarse particulate matter.

The EPA said the region is in attainment for fine particulate matter. Domsky said residents who disobey no-burn day restrictions could face fines but not on the first offense. He said even with pollution control efforts, Valley residents will likely have to look at the brown cloud for a while.

"I think it’ll always be there to some degree. We have made a lot of progress on improving visibility over the last several years, but because we have such dry air and we’re capable of seeing long distances through the Valley, it’s likely to be with us as long as we have development here," Domsky said.
 
If the county exceeds the EPA’s standards on fine or coarse particulate matter levels, it could lose federal highway money, but officials said the region is not in any imminent danger of that right now.