High Ground Level Ozone Concentrations Recorded in St. Louis Region

The U.S Environmental Protection Agency has designated the St. Louis metropolitan area as a

nonattainment area under the current ozone standard. This means the area currently violates the federal

health-based standard, which is based on a three-year average of monitoring data. When concentrations

on individual days reach unhealthy levels, this is known as an exceedance.

The department recently submitted a new eight-hour ozone plan that demonstrates the St. Louis

metropolitan area will attain the federal ozone standard by 2009. The plan relies primarily on federal

regulations requiring cleaner automobiles. Other emissions reductions in the plan include reductions in

pollutants from coal-fired power plants, heavy-duty diesel engine standards and off-road mobile engine

standards. Finally, the continuation of reformulated gasoline and vehicle inspection and maintenance

programs will play an important role in helping the St. Louis area improve its air quality.

High concentrations of ground-level ozone were recorded in the St. Louis area on June 12, 13, 14, 15 and

17. Forecasts indicate that ozone levels may increase again as we move into another hot weekend.

The department recorded high readings at three of the ten Missouri monitors located in the St. Louis area.

These monitoring sites are located in Maryland Heights, Orchard Farm and West Alton.

High concentrations of ozone are considered unhealthy and can cause problems for those with existing

heart or respiratory conditions, or even healthy individuals spending extended periods of time outdoors. In

the general population, an elevated ozone level can lead to irritation of the eyes, nose and throat and

make breathing difficult.

There are several actions that area citizens can take to help reduce ground level ozone. East-West

Gateway's online Air Quality Resource Center (http://www.ewgateway.org/environment/aq/aq.htm)

provides information on what you can do to reduce ozone and lists resources for additional information on

air quality.