DES MOINES - The DNR is forecasting unhealthy levels of airborne particulate matter (soots) Thursday across southeast Iowa. Levels Wednesday were unhealthy for sensitive groups as well.

The Air Quality Index (AQI) is forecast today to reach 109 to 118 across the region, a level considered unhealthy for sensitive groups, such as persons with heart and respiratory disease, the elderly and children. Those persons should avoid prolonged outdoor activity today. Yesterday's AQI reached 110 in the region.

Another pollutant, ozone smog, has been elevated the past several days across southeastern Iowa, but has not reached unhealthy levels. Levels were rising in the mornings throughout the week, but falling off in the afternoons. Extreme western Iowa also has had elevated levels of smog, with an AQI of 100 measured Wednesday near Pisgah, 30 miles north of Council Bluffs. Central Iowa has had moderate air quality the past several days for both particulate matter and smog levels.

"Asthmatics, children and healthy persons planning extended outdoor exertion or vigorous activity today may wish to wait for better air quality," said Brian Button, DNR air quality information specialist. "Those groups are most at risk of respiratory irritation," he said.

A Canadian air mass is expected to bring cooler temperatures and cleaner air into the state later today. Particulate levels will immediately fall as the front passes through the state.

Particulate matter includes solid particles and liquid droplets in the air. Particles less than 2.5 microns (about the thickness of a human red blood cell) pose the greatest health concern because they can be inhaled and accumulate in the respiratory system. Visible smoke is made up of these individual, microscopic particles.

The DNR is asking area residents to consider simple voluntary actions today to avoid the heat while minimizing particulate emissions. Citizens can:

*Avoid or postpone burning of debris until better air quality returns.

*Postpone unnecessary driving or consolidate errands to use the car when pollution controls are warmed and emitting less

*Avoid or postpone use of heavy-emitting two-stroke engines such as gas-powered mowers, weed trimmers and chain saws until evening.

The AQI is a national method of reporting air quality. The higher the AQI, the poorer the air quality. An AQI of 1 to 50 is considered good, an AQI from 51 to 100 is moderate, 101 is unhealthy for sensitive people and 151 and higher is unhealthy for everyone. Most days in Iowa fall into the good to moderate categories.

Iowans can check air pollution levels at www.iowacleanair.com.