The St. Louis area exceeded the 2008 eight-hour ozone standard of 75 parts per billion on five days this year, resulting in air-quality violations this year.

These “exceedances” have caused a violation of the standard based on an average of the last three years of monitoring data, according to a news release issued by the Missouri Department of Natural Resources.

Therefore, the St. Louis area is in violation of the 2008 eight-hour ozone standard and likely will remain a non-attainment area, the release stated.

These violations, according to the re-lease, are further complicated by the U.S. Environmental Protection Agency’s recent announcement the 2008 eight-hour standard is under reconsideration. It is likely to be lowered to be more protective of public health and the environment.

The St. Louis region has successfully monitored attainment with the previous 1997 eight-hour ozone standard of 85 ppb, but the lowered ozone standard will require additional controls to reduce emissions of ozone precursors, which include volatile organic compounds, or VOCs, and nitrogen oxides, or NOx.

Therefore, while emission reduction strategies have been effective in St. Louis, additional controls will need to be implemented, the release stated.

The department will continue to work to protect air quality in the area with an emphasis on developing control measures that are the most effective in terms of cost and emission reductions. Reformulated gasoline, gasoline vapor recovery nozzles, solvent cleaning and other industrial regulations, and the mandatory inspection and maintenance of automobiles in the St. Louis area continue to help reduce emissions.

Ozone season begins April 1 and ends Oct. 31.

Throughout the season, monitors in the St. Louis nonattainment area record the ozone levels at seven sites in Missouri.

The nonattainment area includes St. Louis city and Franklin, Jefferson, St. Charles and St. Louis counties.

Ground-level ozone is produced when VOCs mix with NOx on warm, sunny days with little or no wind.

Man-made sources of VOCs and NOx include power plants, automobiles and trucks and other business and industries.

Exposure to ground-level ozone, or smog, can attribute to health problems.

Those who suffer from asthma, heart disease, emphysema and other respiratory diseases could experience increased breathing difficulty.

Long-term exposure to high levels of ozone can even cause healthy adults to experience breathing difficulty, especially those who exercise or work outdoors.

For additional information about ozone, call the department’s Air Pollution Control Program at (800) 361-4827 or (573) 751-4817.