Seal of Dane County County of Dane
County Executive's Office

Ozone Season Begins in Dane County

June 25, 2008
Dave Merritt, Project Coordinator, (608) 266-9063
County Executive

New Federal Ozone Standard Could Result in More Clean Air Action Days Hot summer weather has returned and so has ozone season. For the fifth consecutive year, the Dane County Clean Air Coalition (DCCAC) will call a Clean Air Action Day when air pollution is forecast to reach unhealthy levels for ground-level ozone. This summer there may be more Clean Air Action Days called as a result of a new and more stringent federal ozone health standard that the U.S. Environmental Protection Agency (EPA) put in place in March according to the DCCAC. In March, EPA adopted new regulations lowering the ozone standard from 84 parts per billion (ppb) to 75 ppb. “Clean Air Action Days are a voluntary way for government agencies, businesses and citizens in Dane County to do their share for cleaner air,” said Dane County Executive Kathleen Falk. “As Dane County continues to grow, we should act to keep our air healthy.” “Everyone has a stake in keeping our air clean and safe,” said Madison Mayor Dave Cieslewicz. “Clean Air Action Days make it easy for the entire community to take meaningful steps toward better air quality.” “More Clean Air Action Days does not mean that there is more air pollution,” said Dave Merritt, DCCAC Project Coordinator. “Dane County residents can expect more Clean Air Action Days because EPA set tougher standards for smog to help improve the protection of public health.” A Clean Air Action Day is triggered when the Wisconsin Department of Natural Resources (DNR) meteorologists notify the DCCAC that an ozone-related air quality watch has been called because weather conditions may produce unhealthy levels of ozone on the following day. “We have made progress in improving the quality of air we breathe in Dane County and throughout Wisconsin, but there is more work to be done,” said Al Shea, Administrator for DNR Air and Solid Waste Division. “The new ozone standard will allow us to build increase public awareness of steps people can take to help reduce ozone. Energy efficiency at home and in our choice of transportation has an impact on air quality, and can also save you money.” In the summer of 2007, DCCAC called four Clean Air Action Days. If the new federal ozone standard had been in place last summer, there would have been ten Clean Air Action Days called. Clean Air Action Day lets people know that ozone could reach an unhealthy level especially for children, older adults, people with asthma and adults engaged in vigorous outdoor activities. Clean Air Action Days also remind people of simple actions they can take to improve the air we all breathe. What is Ozone? Ozone in the upper atmosphere is a good thing, protecting the earth from the sun’s harmful ultraviolet rays. But, ozone found close to the earth’s surface, or ground-level ozone, is a key component of smog and a harmful pollutant. Clean Air Action Days occur on hot days with lots of sun and little or no wind when pollutants (volatile organic compounds (VOCs) and nitrogen oxides (NOx)) “cook” in the hot sunlight to form ground-level ozone. The major sources of VOCs and NOx include: · Cars, trucks and buses · Gasoline storage, transfer and refueling · Large utility and industrial facilities · Industrial use of solvents and degreasing agents · Off-road engines such as construction equipment, aircraft, locomotives, boats and lawn & garden equipment What Can You Do to Reduce Ozone During a Clean Air Action Day, government agencies, businesses and citizens will be asked to do their share for cleaner air and the health of local residents by engaging in ozone-reducing activities. Because half of all Dane County’s ozone-forming pollutants come from everyday activities like driving a car, refueling, or mowing the lawn, area residents can play an important role in reducing emissions. Actions that citizens can take on a Clean Air Action Day to reduce the likelihood of ozone formation include: · Ride the free Metro Transit bus to work or join a car/vanpool: or · Don’t idle. It gets 0 MPG! · Combine errands and reduce trips · Reschedule or delay lawn mowing using gas-powered equipment until after 6 p.m. · Refuel your car after dusk if possible · Conserve energy at home and work by reducing air conditioning and turning off unnecessary lighting CAC member organizations will activate their Clean Air Action Day response plans to help protect air quality and help ensure that Dane County continues to comply with all federal air quality standards. Madison Metro will again this year provide free bus service on the first five Clean Air Action Days to encourage people to leave their cars at home. Clean Air Action Day response plans include alerting all employees via e-mail, limiting vehicle idling and avoiding refueling fleet vehicles until after 6 p.m., reducing or postponing mowing and painting whenever possible and conserving energy by reducing air conditioning and lighting. For more information on Clean Air Action Days, visit the Dane County Clean Air Coalition website at Air Quality Watches and Advisories will be posted on the main DNR internet page,, as soon as they are issued. The Air Quality Hotline is 1-866-DAILY AIR (1-866-324-5924) and will be updated when watches or advisories are issued. To sign up for the DNR listserv and receive watches or advisories by e-mail, go to With EPA's new ozone standard, the federal Air Quality Index (AQI) was adjusted and the "unhealthy for sensitive groups” orange level is triggered at a lower concentration. This is the level the DNR uses to calls air quality watches and air quality advisories.
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