Sky conditions snag Valley right in the thick of things

If you think the air over Phoenix is a little more visible than usual lately, you’re right.

The lack of rain for the past three months along with calm winds have resulted in higher levels of dust in the air around the city. The Arizona Department of Environmental Quality has issued a dust high-pollution advisory for today.

The advisory specifically addresses coarse particulate matter (10 microns or less), particles so small they can enter a person’s respiratory tract. Particulate levels could exceed the federal health standard today.

Exposure to particulates can cause eye, nose, throat and lung irritation (coughing, sneezing, runny nose and shortness of breath). Exposure can worsen such conditions as asthma and heart disease, so people with those conditions, along with older adults and children, should limit their time outside during pollution advisories.

Lack of rain — the official Phoenix rain gauge at Sky Harbor Airport

hasn’t recorded a measurable amount since Aug. 23 — helps keep dust in the air, said Ron Pope, atmospheric scientist with the Maricopa County Air Quality Department.

“It’s a combination of how dry it is and right now, just a stagnant atmosphere,” Pope said. “With light winds, there is very little going on with mixing in the atmosphere. With those conditions, any kind of dust-generating activities in the area means the dust and particulate matter will stick around.”

Rain, or even a breezy day, could help clear the air. The next opportunity for rain is a 10 percent chance in the National Weather Service forecast for Sunday.

“We’re waiting for a (weather) front to break this up and hopefully that will bring some rain with it to help out,” Pope.

Valley residents refer to the layer of dust, smog and other pollutants that’s visible during fall as the “brown cloud.” That phenomenon is most prevalent in the cooler months because of a temperature inversion (a layer of warm air that traps cooler air and pollutants closer to the ground) and more frequent use of fire pits and fireplaces.

With warmer than normal weather in November, use of those devices hasn’t really picked up yet.

“There might be a little bit of that going on; it is starting to cool down at night,” Pope said. “But I don’t think that’s really what this is. We normally see fireplace smoke on weekends. This being midweek, it’s being associated with dust-generating activities and traffic.”

During high-pollution advisories, the Arizona Department of Environmental Quality encourages using these tips and resources to help make the air healthier to breathe.

❚ Avoid or limit wood burning in fireplaces, chimineas, fire pits and other outdoor situations (including at hotels and restaurants and by people or businesses that have permits for open burning).

❚ Avoid using leaf blowers.

❚ Avoid activities that generate dust, such as driving on dirt roads.

❚ Drive as little as possible, car pool, use public transit or telecommute.

❚ Businesses that conduct dust generating operations should be vigilant in their dust-control measures.