Particulate Air Pollution Levels Unhealthy Over the Weekend

For More Information Contact Brian Button 515-281-7832

DES MOINES-Air quality reached unhealthy levels for sensitive groups over the last several days in portions of Iowa because of microscopic particulate matter, according the DNR.

Under the national Air Quality Index (AQI), recent air conditions fell into the orange or "unhealthy for sensitive groups" designation. Other areas of the Upper Midwest also experienced similar air quality over the last several days.

Increased wind and other changes in weather should help Iowa's air return to good to moderate conditions today.

Recent AQI values measured 101 to 141, measured by monitors located in Clinton, Linn, Palo Alto, Scott, and Van Buren counties. Unhealthy levels were measured over the weekend and Tuesday.

The higher the AQI, the poorer the air quality. An AQI of 1 to 50 is green or good, 51 to 100 is yellow or moderate, 101 and higher is orange or unhealthy for sensitive groups, 151 and higher is red or unhealthy for everyone, 201 and higher is very unhealthy and 301 and higher is hazardous.

Recent levels were in the orange classification where prolonged, heavy exertion outdoors could increase the likelihood of symptoms in sensitive individuals such as persons with respiratory and heart disease, the elderly and children. Iowans may have noticed recent hazy skies and decreased visibility, characteristic of the light scattering nature of the microscopic airborne particles.

The cause of the pollution episode is likely airborne sulfates or nitrates, but air officials won't know for sure until monitor filters undergo analyses at multiple laboratories across the nation. This type of pollution is often regional in nature, caused by emissions that travel and react over great distances.

What is Particulate Matter?
Particulate matter is a generic term for small bits of solid materials, liquid droplets, or aerosols in the outdoor air. Fine particles less than 2.5 microns--about the size of a human red blood cell--pose the greatest health risks and are regulated pollutants. Some can be seen only with an electron microscope.

Particulates originate from many sources such as direct emissions of smoke, or form from airborne reactions of sulfur and nitrogen oxide gases depending on the air chemistry, time of year, and weather.