Ozone action days are declared when high levels of ground ozone – formed by pollutants from cars, power plants, industrial boilers, refineries, chemical plants and other sources – react chemically with sunlight and accumulate to unhealthy levels.

Ozone is one of several pollutants that make up "smog" – a reddish-brown haze that forms when air quality is particularly poor. Summer days are more prone to high ozone levels, especially when temperatures are above 90 degrees and winds are less than 10 miles an hour.

High concentrations of ozone can cause shortness of breath, coughing, wheezing, headaches, nausea, and throat and lung irritation. Poor air quality as a result of high ozone levels can trouble people who suffer from bronchitis, pneumonia, emphysema, asthma and colds. Children and anyone who spends a lot of time exercising or working outdoors have a higher risk of respiratory problems caused by ozone.

Ground-level ozone is the most prevalent air pollutant in Texas and the nation, according to the CLEAN AIR Force of Texas. People in nearly 100 major cities are periodically exposed to harmful concentrations of ozone.  In Texas, four urban areas with nearly 50 percent of the state’s population do not meet federal standards for ozone: Houston-Galveston; Dallas-Fort Worth; Beaumont-Port Arthur; and El Paso. Other areas in Texas are very close to not meeting federal standards.

To help combat this problem, the CLEAN AIR Force of Central Texas educates Central Texas residents on how they can help reduce air pollution. The organization’s Clean Air Partners Program (of which LCRA is a member) asks Central Texas businesses to pledge to make a good-faith effort to reduce ozone-related emissions by 10 percent in three years. To learn about ozone and how you can help lower emissions, visit www.cleanairforce.org.