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Oh No, Ozone! 5 Ways You Can Reduce Air Pollution

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by Lily Lowder
April 5, 2021

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In the San Antonio region, ozone season runs from March to November.

March means different things to each San Antonian. For some, the warmer weather reminds us of sunnier days ahead. For others, spring break means avoiding the Riverwalk during the next six months of tourist season. For many, March begins our seasonal ritual of popping bottles of Zyrtec to ward off the onslaught of pollen.

At the Alamo Area MPO, March heralds the start of ozone season, when air pollution is worse than normal. Every year, the beginning of ozone season requires us to evaluate how transportation and our work impact air quality. We also reflect on what we – and you – can do as individuals to reduce air pollution.

What is the ozone season?

According to the Alamo Area Council of Governments, the ozone season is a period of time in which ground-level ozone, which is the most common type of air pollution we have in the Alamo Region, typically reaches its highest concentrations in the air we breathe.

In this region, the ozone season stretches from March through November. Ground-level ozone reaches its highest concentrations during these months because ozone forms when nitrogen oxides mix with volatile organic compounds in intense sunlight, and sunlight is strongest from April through November. It is during this time that we are most likely to have exceedances of the National Ambient Air Quality Standard for ground-level ozone. Due to additional atmospheric conditions at certain times during these months, April through May and August through September tend to have the highest concentrations of ground level ozone.

How does transportation impact air quality?

Emissions from industrial facilities, electric utilities, motor vehicle exhaust, gasoline vapor and chemical solvents are some of the major sources of the air pollutants nitrogen oxides (NOx) and volatile organic compounds (VOC). When these pollutants react together in sunlight and heat, ozone is formed.

Chart showing emissions sources

How can I help?

Everyone can do their part to reduce their contribution to ozone pollution, particularly related to vehicle emissions.

  • Make smart transportation choices. Instead of driving alone for trips, opt for more efficient transportation choices, such as public transit, carpool, biking, or walking. Or avoid the trip altogether by conducting your meetings virtually! If you drive regularly, consider purchasing a fuel-efficient hybrid or electric vehicle.
  • Service your vehicles frequently. Getting your car serviced regularly will increase your fuel efficiency and add to the car's life. Get your oil changed on time and have your car checked for problems regularly. Make sure your tires are properly inflated, reducing friction between the rubber and the road. By ensuring your car is running well you can increase your mileage AND you can save up to $200 a year.
  • Slow down. Because wind resistance builds up so much with higher speeds, every mile per hour you drive over 55 decreases your fuel economy by 2%. In other words, if you're driving 80 mph you'll cut your fuel economy by half.
  • Go in instead of using the drive-thru. The drive-thru has become a staple of many people’s lives but it also makes us contributors to ground-level ozone. If you spend just 5 minutes in a drive-thru each weekday, that's 1300 minutes or more than 21 hours per year. By skipping the drive-thru and walking into businesses, we can all take the first steps to cleaner air.
  • Go green. Limit waste; reducing the amount of waste you produce and reusing products are best because there is no reproduction process involved. And plant a tree; an acre of trees absorbs enough CO 2 over one year to equal the amount produced by driving a car 26,000 miles. Eco-friendly actions that reduce electricity and water consumption, waste, and more will all do their part to improve air quality.

Learn more about the relationship between transportation and air quality – and what you can do to reduce your environmental footprint – on the AAMPO website. And don’t forget to track your smart transportation trips on Alamo Commutes so you can earn rewards and special prizes; “non-trips” like telecommuting and brown bag lunches count too!

If you have any questions about how you can reduce your vehicular emissions, email Lily Lowder at