Air Quality

Clean Air

The City of San Marcos is committed to addressing air pollution to improve the overall well-being of our community. We achieve this goal by implementing municipal ordinances and working with regional organizations to address air quality concerns that impact everyone. This collaborative effort is facilitated through the Air Central Texas initiative of the Capital Area Council of Governments.

For more information and ways you can help keep our air clean, visit Air Central Texas.

Introducing our Air Quality Index (AQI) reader! 

This tool provides real-time data on the cleanliness of the air you're breathing. It measures invisible pollutants and translates them into an easy-to-understand scale, helping you know at a glance whether the air is clean and safe or if precautions are needed. It's your window to the air quality in your area, updated constantly for your well-being.

Visit to see a more detailed current Air Quality Index (AQI)!

A great way to improve air quality is to take the bus, ride a bike, or carpool! 

Here are some ways you can help Keep Central Texas Air Clean!

Reduce vehicle emissions:
  • Use public transportation, carpool, walk, or bike whenever possible.
  • Combine errands to minimize car trips.
  • Keep your car well-maintained to reduce emissions.
  • Avoid idling your car's engine.
Support clean energy and environmental initiatives:
  • Support the use of clean and renewable energy sources.
  • Reduce, reuse, and recycle materials.
  • Plant trees and shrubs.
  • Advocate for ozone-friendly policies.
Reduce emissions from other sources:
  • Use energy-efficient appliances and lighting.
  • Limit the use of aerosol sprays.
  • Conserve water.

By taking these simple actions, you can help to reduce ozone pollution and improve air quality for everyone.

Graphic that describes the formation of Ground level Ozone.

What is ground-level ozone:

Ground-level ozone is a colorless gas created when natural and human-made emissions of nitrogen oxides (NOx) and volatile organic compounds (VOCs) react with sunlight. These emissions primarily come from vehicle exhaust, but also originate from industrial processes, power generation, and even some natural sources.

Ozone Action Days

In Central Texas, ground-level ozone is the main air concern. Though the region mostly meets federal air quality standards, there are occasional days when ground-level ozone reaches unhealthy levels for sensitive groups.