Office of Sustainability
Ozone and Health


Contact Us
P.O. Box 839966
San Antonio, TX 78283-3966

Physical Address
1400 S. Flores, Unit #2
San Antonio, TX 78204




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  • Douglas Melnick Email Douglas Melnick
    Chief Sustainability Officer

Air and Heath - photographer Joe Diaz.

Ozone Effects On Your Health

According to the United States Environmental Protection Agency (EPA), ozone in the air can be harmful, especially on hot sunny days when ozone pollution can reach unhealthy levels. Even relatively low levels of ozone can cause health problems and can be serious in people with respiratory diseases such as asthma. Groups, including children, the elderly and outdoor workers are most sensitive to increased levels of ozone.

Health Impacts of Ozone Pollution

The City of San Antonio commissioned an environmental firm to estimate the health and cost impacts of changes in outdoor ozone levels. The model estimates that increases in ozone levels results in 19 respiratory deaths and improvements in ozone levels leads to twenty-four avoided deaths. On an economic level, the cost associated with these respiratory deaths is estimated to be $170 million. However, the avoided cost of twenty-four deaths is estimated to be $220 million. The full report can be viewed here.

2010-2014 Baseline Ozone Levels: 4,768 Respiratory Deaths in Bexar County. Ozone Standard Violation: 19 Additional Deaths. Ozone Standard Attainment: 24 Avoided Deaths.

Reducing Individual Contribution to Air Pollution

You can help prevent ozone pollution by sharing a ride, taking the bus, walking or riding a bike, taking your lunch to work, walking or avoiding drive through lanes if eating out, and waiting until after 6:00 PM to fill your car with gas or mow the lawn. For more tips, visit “Breathe Today. SA Tomorrow”. Help keep our air healthy!

Reducing Exposure to Air Pollution

While exercising outdoors can be detrimental during high ozone days, the health benefits of being physically active far outweigh the risks from poor air quality in San Antonio. Residents can reduce risks associated with high ozone levels by signing up to receive daily air quality forecasts and ozone alerts from the Texas Commission on Environmental Quality.

Air Quality Index (AQI)

The AQI is an index for reporting daily air quality. It tells you how clean or polluted your air is, and what associated health problems might be a concern for you. The AQI focuses on health problems you may experience within a few hours or days after breathing polluted air. EPA calculates the AQI for five major air pollutants regulated by the Clean Air Act: ground-level ozone, particle pollution (also known as particulate matter), carbon monoxide, sulfur dioxide, and nitrogen dioxide. For each of these pollutants, EPA has established national air quality standards to protect public health. Ground-level ozone is the pollutant of concern in the San Antonio area that poses the greatest threat to human health.

The EPA has assigned a specific color to each AQI category to make it easier for people to understand quickly whether air pollution is reaching unhealthy levels in their communities. You can find out the daily air quality index levels of health concern for San Antonio at the Texas Commission on Environmental Quality’s “Today’s Air Quality Forecast

Air Quality Index Levels of Health Concern Numerical
Good 0 to 50 Air quality is considered satisfactory, and air pollution poses little or no risk.
Moderate 51 to 100 Air quality is acceptable; however, for some pollutants there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.
Unhealthy for
Sensitive Groups
101 to 150 Members of sensitive groups may experience health effects. The general public is not likely to be affected.
Unhealthy 151 to 200 Everyone may begin to experience health effects; members of sensitive groups may experience more serious health effects.
Very Unhealthy 201 to 300 Health alert: everyone may experience more serious health effects.
Hazardous 301 to 500 Health warnings of emergency conditions. The entire population is more likely to be affected.