ADEQ talks ozone

Ozone. It’s a good thing—as long as it’s six to 30 miles up in the stratosphere, where we can’t breathe it.  But when the summer heat stimulates chemical reactions of air pollutants to form ground-level ozone, it’s a bad thing. Human action has contributed to the depletion of good ozone and the creation of bad ozone, and the results can be pretty ugly.

Ozone occurs naturally in the stratosphere. The thin layer of ozone up there shields the earth from harmful ultraviolet rays that can cause skin cancer, cataracts, impaired immune systems and damage to plants.  But chemicals developed in the 20^th century—mainly chlorofluorocarbons, hydrochlorofluorocarbons and halons used as propellants, coolants and fire extinguishers—began to deplete the protective layer of ozone. In 1984 a hole in the layer was discovered over Antarctica, prompting the creation in 1987 of the Montreal Protocol on Substances that Deplete the Ozone. Since then, 197 nations that have signed the treaty have made significant progress in phasing out the production and use of ozone- depleting substances. As a result, the hole is shrinking and is expected to close during this century.

While protecting the ozone layer up high, we need to prevent its formation nearby, and summer is the time to be most diligent. Ground-level ozone begins to rear its ugly head when temperatures rise in urban areas, where voluminous emissions from gasoline motors and factories and fumes from volatile organic compounds like oil-based paint, pesticides, cleaners and gasoline react in heat and sunlight to form dangerous amounts of ozone, the main ingredient in smog.

High concentrations of ozone at ground level can cause shortness of breath, coughing, wheezing, headaches, nausea, and eye and throat irritation. Ozone is especially dangerous for persons with lung disease, children, the elderly, and outdoor exercisers. Children are at risk for respiratory problems because their lungs are still developing and they breathe more rapidly, inhaling more air pollution per pound than adults. Adults who exercise heavily may increase their intake of air by as much as 10 times their level while at rest.

Ground-level ozone also damages vegetation and ecosystems.  According to the Environmental Protection Agency, it is responsible for an estimated $500 million in reduced crop production each year in the United States. The Arkansas Department of Environmental Quality works with Metroplan, the Central Arkansas Clean Cities Coalition, the Arkansas Department of Health and the Arkansas Highway Department to present Ozone Action Days, a program to make air quality information available to the public in central Arkansas. Counties included are Pulaski, Faulkner, Lonoke and Saline. From May through September, ADEQ monitors ozone levels. An Ozone Action Day Advisory or Alert will be declared in central Arkansas when the ozone levels for the metropolitan area are forecast to exceed the National Ambient Air Quality Standards, which are set by the EPA. Advisories are issued when prolonged outdoor exertion is unhealthy for sensitive groups (i.e., children and persons with asthma or other breathing problems). Alerts are issued when prolonged outdoor exertion is unhealthy for everyone. 

ADEQ director Teresa Marks encourages public agencies, private businesses and individuals to do what they can to reduce ground-level ozone formation to minimize related health risks when an Ozone Action Day advisory or alert has been issued. “Individual actions can make a big difference when we all work together,” she said.

The following suggestions can help reduce ground-level ozone and are especially important on days when an ozone advisory or alert has been issued:

Limit driving and excessive motor idling.

Keep automobiles well-tuned.

Don’t do lawn chores with gasoline-powered equipment. (Every summer day in the Little Rock metro area, gasoline-powered lawn and garden equipment releases more pollutants into the air than a typical large industrial plant.)

Don’t use products that release fumes or evaporate easily.

Don’t refuel during the day; wait until dark.

Don’t overfill or top off your gas tank.

ADEQ’s daily ozone forecasts are available on the agency’s website, http://www.adeq.state.ar.us/. Additional information can be found at the Ozone Action Days site, http://www.ozoneactiondays.org/.