An 11-year-old asthma patient provided frightening details.

“I started having chest pains and it was hard to breathe,” said Katie Walsh of Marietta, recalling her effort to play softball on a high-ozone day last month. “It was hard for me to keep going.”

Katie, who has lived with asthma since she was 6, has made adjustments to Atlanta’s high-ozone summers, said her mother, Ann Walsh.

This summer, for example, Katie is attending an indoor day camp. When she does venture outside, she has to use an inhaler more often than usual.

“It’s not an ideal situation,” said Ann Walsh. “She can’t enjoy being outdoors without suffering side effects.”

Mary Jane Richman, a nurse who is manager of pulmonary diseases at Children’s Healthcare of Atlanta, told the GRTA board that asthma is the leading national cause for children missing school, and also the No. 1 cause of inpatient admissions to Children’s Healthcare.

Almost 34,000 children in Atlanta suffer from asthma, and Richman said a study during the 1996 Olympic Games suggested that their health is directly affected by the driving behavior of adults.

During the 17 days of the Olympics, when traffic was significantly reduced, children’s asthma-related admissions to Children’s Healthcare declined as much as 42 percent compared to the period immediately before and after the Olympics, Richman said.

“This is a classic example of how, when the community does pull together, we can significantly improve our air,” she said.

The air quality in the Atlanta region does not meet the standards of the federal Clean Air Act, and was a major reason the General Assembly created GRTA in 1999. Emissions from cars, trucks and buses are a major source of ozone in the metro area.

GRTA is working to create a transportation system that improves air quality and relieves congestion by providing more transportation choices, including new roads, HOV lanes, buses, van pools, trains and bicycle lanes.