Pollution clouded Iowa early this weekend

What is fine particulate pollution?

According to Todd Russell -- an air monitor for the Iowa Department of Natural Resources -- it is made up of tiny particles as a result of combustion from industrial plants, vehicles and even wood-burning stoves.

How tiny?

While the average human hair is measured between 60 and 80 microns in diameter, fine particles are no larger than 2.5 microns in diameter.

These miniature molecules resulted in an air quality advisory for Iowa starting at noon on Friday as numerous cities recorded more than 35 micrograms per cubic meter, the Environmental Protection Agency's 24-hour threshold for fine particles.

Emmetsburg was the lone northwest Iowa city on the list with 45 micrograms per cubic meter, compared to 47 in Waterloo, 44 in Davenport and 43 in Des Moines.

"The alert was scheduled to expire at noon on Saturday," Russell said. "Most of the state was well cleared out prior to that."

At 4 a.m. Monday morning, fine particulate pollution in Emmetsburg was reported at 35 micrograms per cubic meter. By noon, that number was reduced to two micrograms per cubic meter.

The change was largely due to west and northwest winds that picked up and carried the pollution out of the area. Weather and pollution are commonly related.

"Predicting air pollution is like predicting weather; in fact, they're tied together pretty closely," Russell explained.

This past weekend, a large, high-pressure system forced warm air over a thin layer of cool air near the surface, holding stagnant, polluted air in place.

"Until a system moves in and allows that system to move out, we get stuck in a blanket of dirty air," Russell stated.

That blanket was shared with much of the Midwest, including the Chicago, Ill., and Milwaukee, Wis., areas, as well as a portion of Minnesota.

"When we have temperature inversions and mixing, we breath our own stew as well as contributions from wherever the wind came from," Russell said.

He added that widespread regional pollution happens two or three times each winter, when pockets of stagnant air are more common.

When this happens, individuals with respiratory or heart disease, the elderly and children are at the highest risk and should avoid prolonged, outdoor exertion until air quality conditions improve.

Those individuals do not need to worry about pollution problems in the near future as cold temperatures and winds from the west and northwest are expected to regulate the region's air quality.

"I would not anticipate issues in your part of the state," Russell concluded.

Pollution conditions may be monitored at www.airnow.gov.