PHOENIX - Monsoon storms send huge walls of dust across parts of Arizona, sometimes snarling traffic on roadways and knocking out power.
An Arizona researcher who studies them says there could be hidden health impacts for millions of people living in the state's dust zone as well.
William Sprigg, of the University of Arizona's Institute of Atmospheric Physics, said dust storms - or haboobs - carry a noxious mix of fungi, heavy metals from pollutants, chemicals and bacteria that could lead to cardiovascular and eye disease, and other illnesses.
"We already know the cost of these storms in general," he told the Arizona Republic. "I would like to see a much more thorough examination of the effects of the dust on the region."
The National Weather Service issues warnings about dust storms but does not keep records in the same way as it does for temperature or precipitation.
The storms aren't new, but the impact was realized a year ago when a major one rolled through Phoenix. That storm had a wall of dust almost 1.5 miles high and 100 miles wide, and it deposited some 40,000 tons of sand and dust in just two hours.
The storms typically develop when cold air in thunderstorms plummets to the ground.
The Phoenix area has seen three smaller dust storms in the past week that felled tree limbs and power poles.
Sprigg is working with the weather service and health agencies on a model to predict when the dust storms will hit.
Health and environmental officials then would know whether to issue warnings to people who are at risk for dust-related health complications, he said.
"They have a tremendous economic and social impact that has been very, very difficult to nail down," Sprigg said. "But we know enough now that we can tell people a lot more about what they are being exposed to."
The difficulty in determining the relationship between dust and human health is due to limited funding and a lack of routine soil sampling and analysis, he said.
On StarNet: Go to azstarnet.com/video to see a time-lapse video of a dust storm rolling into Phoenix in July 2011.