Air quality alert issued for Houston

The record heat is translating into poor air quality around Houston. The city has already seen nearly a dozen days during season where the air was considered unhealthy to breathe.

An Ozone Action Day is issued when the air quality is poor enough to alert the public.

The concern stems from ground-level ozone being produced when the heat mixes with various pollutants, such as vehicle exhaust. The air, when breathed in over prolonged periods, can be dangerous or even fatal.

“When scientists are able to look back at more and more data, they find that more people die on the day or day after we have these smog days," explained Dr. Daniel Cohan, Associate Professor in the Civil and Environmental Engineering department at Rice University. "So this is an unhealthy, even deadly, pollution in the air and it’s something we have to take seriously.”

This year alone has already been particularly bad, according to Dr. Cohan.

“We’ve already had three code red days in Houston," said Dr. Cohan. "Those are days when the air is unhealthy, even for all people, to be breathing and all of last year we only had three and the year before we only had two so to be at three just in May, is an ominous start for the year."

Those colors are determined by an air quality index chart. For example, an orange day will typically warrant on Ozone Action Day. It's on those days that sensitive groups, like children or the elderly, are encouraged to limit their outdoor afternoon activity. 

“Sunlight and heat cook up other pollution that we emit from our cars, that we emit from our factories, and they cook it up together to form ozone smog," said Dr. Cohan. He also said that Houston seems to have two ozone seasons: one right now, from late April to early May, and then again in August through September.

Carpooling, using less gas and conserving energy are all different ways you can help keep air pollution levels low.