Ozone season is typically August through early October and is a time when it is most likely ground-level ozone is going to form, said Heather Jefts, a Central Texas Clean Air Coalition member.
Information from the Environmental Protection Agency states that ground-level ozone is not emitted directly into the air but is created by chemical reactions in the presence of sunlight. Breathing ozone can trigger a variety of health problems, particularly for children, the elderly and people with lung diseases such as asthma. It can also have harmful effects on sensitive ecosystems.
The EPA regulates ground level ozone and uses it to monitor air quality, which has been worse than normal this year, Jefts said. About 67 percent of emissions associated with ozone formation in the Austin-Round Rock region are attributable to on-road and off-road vehicles, Travis County Judge Sarah Eckhardt said.
If the Austin-Round Rock region exceeded the 70 parts per billion standard in 2019 or beyond, the region could be designated by the EPA as “non-attainment” for ozone, Eckhardt said. The designation could include just Travis County (where the two regulatory monitors for the region are located), or it could include all or part of the 5-county region: Bastrop, Caldwell, Hays, Travis and Williamson.
Given the region’s “positive and proactive” ozone history, it is almost certain that a designation of non-attainment for the Austin-Round Rock region would be classified as “marginal,” Eckhardt said. Under current rules, this applies to areas where the design value is 71-81 parts per billion.
The non-attainment region would be given three years to come into attainment.
If the region did not come back into attainment status by its target date it could be reclassified as “moderate non-attainment,” Eckhardt said. This would open up a host of additional requirements and have implications for 20 years or longer.
Jefts said residents can help improve levels by not doing high-ozone activities such as filling the car with gas or mowing the lawn between 9 and 11 a.m, the period when most of the ozone will form for the day. She said simple scheduled changes can have a huge impact on air quality.