KANSAS CITY, Mo. -- The Kansas City metro area exceeded ozone standards six times during the ozone warning season in 2009.

The eight-hour standard was set in 2008 at 75 parts per billion. The 2008 standards are likely to be made more restrictive by the Environmental Protection Agency, the agency announced recently.

The violations will likely make the metro area a non-attainment area.

Kansas City has hovered just below the 1997 eight-hour ozone standard of 85 ppb, which made it an ozone maintenance area. Those areas are required to have a plan with contingency control measures to reduce emissions of ozone precursors.

A non-attainment designation would require even more stringent controls to bring the area into attainment of a lowered ozone standard.

Ozone season begins April 1 and ends Oct. 31. The ozone levels are monitored in five sites in Missouri and three in Kansas.

According to the EPA, ground-level ozone is produced when volatile organic compounds mix with oxides of nitrogen 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.

The EPA said 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.