Today is an Ozone Action Day in Houston. This means that conditions are right for formation of dangerous ozone air pollution. Ozone forms on hot, still, dry, sunny days, when ozone precursors combine in the atmosphere via a photochemical reaction.
When conditions are right for ozone formation, there are steps you can take to (1) limit your exposure to harmful ozone pollution and (2) limit your contribution to ozone precursor pollution. In order to take these steps, you need to know when ozone might be a problem. You can sign up for email or text alerts about Ozone Action Days from the Texas Commission on Environmental Quality. You can also check the daily air quality forecast from the Environmental Protection Agency (EPA) at airnow.gov.
Once you know ozone might be a problem on a given day, such as today, you should take the following steps.
Limit your Exposure
Ozone Actions Days occur when ozone is predicted to reach levels that are unhealthy for sensitive groups, which is anything in the 71-95 parts per billion range. Groups sensitive to ozone pollution include children, the elderly, and those with heart respiratory diseases. If you or a family member is unusually sensitive to ozone pollution, you should take the following steps recommended by the EPA:
Reduce prolonged or heavy outdoor exertion. Take more breaks, do less intense activities. Watch for symptoms such as coughing or shortness of breath. Schedule outdoor activities in the morning when ozone is lower.
People with asthma should follow their asthma action plans and keep quick- relief medicine handy.
How do you know when ozone has reached levels unhealthy for sensitive groups? By checking ozone levels in real time with the Houston Clean Air Network. This website was developed by Air Alliance Houston and the University of Houston and provides the public with free, up-to-the-minute information about ozone pollution. The Houston Clean Air Network is also available as a free smartphone app for iPhone and Android called “OzoneMap”.
The Houston Clean Air Network and OzoneMap will tell you if and when ozone pollution reaches 96 parts per billion or more, at which point anyone might begin to experience health effects. Fortunately, we only have a few days each year in Houston when ozone pollution reaches this level.
Limit your Contribution
The other thing you can do on an ozone action day is limit your contribution of ozone precursor pollutants. The two ozone precursors are nitrogen oxides, or NOx, and volatile organic compounds, or VOCs. Many human activities, such as driving, release NOx and VOC pollution into the atmosphere. These are harmful pollutants in their own right, but they are also the cause of harmful ground level ozone. By limiting your contribution to these precursors, you can do your part to prevent ozone pollution in Houston. On an Ozone Action Day, you should consider taking some or all of the following steps.
- Limit driving. Cars produce both NOx and VOCs. You can limit driving by carpooling, using public transportation or, avoiding car trips all together. You can also stay off the road during heavy traffic times (this has the added benefit of keeping our of Houston lovely rush hours).
- Avoid filling your gas tank. Gas pumps emit VOCs. If you must fill your gas tank, try to wait until the end of the day, when it begins to get cooler. You should also avoid topping off your gas tank, which can cause spilling and excessive VOC emissions.
- Don’t idle. This one is simple: don’t leave your engine running when your car isn’t moving. This saves gas, and the air we breathe.
- Turn off engines. In addition to idling vehicles, we sometimes use other small appliances or equipment with gas motors. On an Ozone Action Day, you should not use a lawn mower, leaf blower, or anything else with a gas engine in the middle of the day. Wait for the cooler afternoon hours to turn on these small gas engines, which produce large amounts of ozone precursors for their size.
- Reduce energy usage. Most of our energy still comes coal and natural gas plants that produce large amounts of zone precursors. You can reduce your energy use by turning off lights and appliances, and by turning up your air conditioning when you leave your house for the day. You can also skip the dryer and line-dry your clothes. (Remember, Ozone Action Days are hot! You should have no trouble line-drying your clothes on a typical Action Day.) There are many resources out there with tips for reducing energy usage, which is also one of the best strategies to combat climate change. One source we discovered recently is littlestepsbigimpact.com from Omaha, Nebraska.
Together, the small actions will combine to have a big positive impact on ozone pollution in the Houston region. By limiting our exposure to ozone, we protect our health and our family’s health. By taking small steps to reduce our contribution to ozone precursor pollution, we help to keep Ozone Action Days like today to a minimum.