ASK 2: How are low traffic volumes impacting our air quality in Houston?

HOUSTON – At KPRC 2, we’re dedicated to keeping Houstonians informed. As part of our new Ask 2 series, the newsroom will answer your questions about all things Houston.

The question: How are low traffic volumes impacting our air quality?

The answer: We’ve seen a dramatic drop in traffic volumes on our highways as a result of the COVID-19 stay-at-home order, and that got a lot of you thinking: how is that impacting our air quality?

I took a closer look at this, and this is what I found.

Experts said, even though some areas did see big improvements in terms of air quality, according to research done at Texas A&M, other areas weren't as dramatic.

Images around the world, specifically in China show the impressive reduction in pollutants.

So, what exactly is the status of Houston’s current air quality condition?

Research done by Gunnar Schade, with Texas A&M, looked at air quality monitoring data from stations around town, three weeks before and after the social distancing order.

This research focused on nitrogen oxide pollutants, which mostly come from car traffic.

According to these results, changes in air quality were not uniform.

"When you look at nitrogen oxide, you can clearly see that traffic has been reduced because the levels of nox have gone down, some places very much, call that dramatic if it goes down by 50%, in other places not so much," said Gunnar Schade, Texas A&M.

For example, Deer Park did not see any major changes in terms of air quality.

Areas near major highways did see dramatic improvements, including the Aldine area near the North Freeway, which saw a 50-percent drop in nitrogen oxide pollutants.

Also, the North Loop near the North Freeway also saw consistent reductions, largely because of the major loss of freeway traffic during all times of the day, according to Schade.

The Bayland Park area was interesting though, even though nitrogen oxide levels decreased during peak rush hour times, throughout the rest of the day:

"There's not much difference at all, before or after the state order to stay at home," according to Schade.

It's important to note, according to Schade, fine particulate matter levels, which are the tiny particles in the air that reduce visibility and cause the air to appear hazy when levels are elevated, have increased, not decreased, since the social distancing measures were put in place.

Air traffic is also a contributor to our air quality. According to Schade, their emissions are smaller than car traffic here in Houston.

Air traffic’s biggest emission is carbon dioxide, and those reduction levels are prominently seen around the airports.

If you have any more questions, regarding our air quality, the Harris County Pollution Control Services Department can help, please visit their website.