Ozone Season Returns to Houston

Spring is coming to Houston, and with it the start of ozone season. You probably haven’t thought about ozone yet this year, and with all the cold weather we’ve had, you could be forgiven. But Houston’s ozone season officially began on March 1, and it may be time to start thinking about this pernicious air pollutant once again.

First we should remember that 2015’s ozone season begins amid a proposal by the Environmental Protection Agency to lower the federal ozone pollution standard. Comments on that proposal were due this week. Air Alliance Houston, with help from students at the University of Houston Law Center, submitted comments calling for a standard as low as 60 parts per billion. The best science of the day indicates that such a low standard is needed to protect public health.

Meanwhile our Governor Greg Abbot, along with Governors from ten other states, ignored public health needs and asked the EPA not to update the ozone standard again, ever. Governor Abbot et. al. claim that the new ozone standard will cost billions of dollars and 1.4 million jobs nationwide. This claim ignores a recent EPA study of the results of the Clean Air Act from 1990 to 2020, which estimates that benefits from implementing the Act exceed costs by a factor of more than 30 to 1.

So there are some hard questions about what the ozone standard will be in the future. But putting those aside for right now, what do you need to know for 2015’s ozone season?

First, you should know that there are fewer and fewer bad ozone days each year in Houston. We experienced 14 violations of the eight-hour ozone standard in Houston in 2014, down from 24 in 2013 and more than 200 in the ‘80’s. Ozone pollution has gotten much better in Houston, but there are still some days when it presents a real public health risk.

Second, you should know that EPA issues daily ozone forecasts at Airnow.gov and that the TCEQ relays these daily forecasts online, via email, and via Twitter.

Finally, you should know that there is a better way than daily forecasts to get information about ozone in Houston: real-time information available via the Houston Clean Air Network.

Ozone forecasts may give you some idea what to expect, but they aren’t very accurate. In 2014, with 15 ozone action days forecasted, only 8 were actual exceedances of the eight-hour ozone standard, with 6 exceedance days occurring outside of predicted action days.

2014 Ozone Venn Diagram

In 2013, with 25 Ozone Action Days, 9 represented actual exceedances, with 15 exceedance days going unpredicted.

2013 Ozone Venn Diagram

This means that Ozone Actions Days correctly predicted actual exceedances about one half of the time in 2014 and only one third of the time in 2013.

The Houston Clean Air Network website and smart phone app takes the guesswork out of the equation, allowing you to check ozone levels in real time when and where you are.

When should you check the Houston Clean Air Network? On days when ozone formation is likely: hot, dry, clear, and sunny days.

An ozone forecast or an email alert from the TCEQ may remind you when these days occur, but ultimately it is up to you to check whether ozone is an issue when and where you are. Most time, you will find that it is not. Sometimes, though, you may find that isolated plumes of ozone in your area mean that limiting outdoor activity might be a good idea. This is especially true if you or someone you love is  a member of an unusually sensitive group: children, the elderly, or those with respiratory illnesses such as asthma.

So whether you use forecasts, houstoncleanairnetwork.com, the OzoneMap app, or some combination of them all, it’s time to start thinking about ozone again in Houston. Hopefully there won’t be many ozone days this year, but when they come, you’ll be prepared.