Air Quality Unhealthy Monday in Clinton County

July 12, 2005

DES MOINES-Air quality reached unhealthy levels for sensitive groups Monday in Clinton County, according to the DNR, due to ground-level ozone, the main component in photochemical smog.

Based on the national Air Quality Index (AQI), pollution levels reached 106, in the orange or “unhealthy for sensitive groups” designation. Scott County had moderate air quality.

The AQI reports pollution levels using a color-coded and numerical range for pollutants. 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 to 150 is orange or unhealthy for sensitive groups, 151 to 200 is red, unhealthy for everyone. Rarely monitored are purple for very unhealthy (201 to 300) and maroon for hazardous (301 to 500.)

Ozone smog forms when emissions from vehicles, utilities and boilers and fumes from paints, gasoline and chemicals “cook” or react in sunlight and warm temperatures to form ground-level ozone, a colorless gas capable of irritating lung tissue.

Levels today remain elevated in the moderate category, as sinking air ahead of a low pressure system from Hurricane Dennis is preventing vertical mixing of air layers.

Last year, no unhealthy ozone levels were monitored in Clinton County. On June 24, the AQI also reached 101 in the Clinton area due to ozone, with thunderstorms clearing the air by the following day. The vast majority of days fall into the good to moderate categories. Iowa typically experiences several days of unhealthy air annually.

For more information contact Brian Button 515-281-7832