2016 air pollution data for Texas

By Luke Metzger

Today we released Our Health at Risk: Why Are Millions of Americans Still Breathing Unhealthy Air?, which examines air pollution data for 2015. We also obtained preliminary data from the EPA for 2016 (the data will officially be considered final on May 1, but we expect few if any changes). So how did Texas metro areas stack up?

In general, air pollution improved in Texas in 2016, with a few exceptions. There were more smoggy days in Houston and more sooty days in El Paso, Brownsville and McAllen (increases italicized below). Here are the specifics for each metro area (and the methodology is below):


56 smog days in 2015, 43 smog days in 2016

Austin-Round Rock

61 smog days in 2015, 39 smog days in 2016

13 sooty days in 2015, 10 sooty days in 2016

Beaumont-Port Arthur

55 smog days in 2015, 47 smog days in 2016


6 smog days in 2015, 4 smog days in 2016

17 sooty days in 2015, 28 sooty days in 2016

Corpus Christi

16 smog days in 2015, 16 smog days in 2016

33 sooty days in 2015, 26 sooty days in 2016 


33 smog days in 2015, 22 smog days in 2016 

Dallas-Fort Worth-Arlington

107 smog days in 2015, 98 smog days in 2016

98 sooty days in 2015, 59 sooty days in 2016 

El Paso

104 smog days in 2015, 86 smog days in 2016

59 sooty days in 2015, 86 sooty days in 2016

Houston-The Woodlands-Sugar Land

101 smog days in 2015, 107 smog days in 2016

171 sooty days in 2015, 102 sooty days in 2016


56 smog days in 2015, 34 smog days in 2016


41 smog days in 2015, 30 smog days in 2016 


20 smog days in 2015, 15 smog days in 2016

17 sooty days in 2015, 11 sooty days in 2016


8 smog days in 2015, 2 smog days in 2016

19 sooty days in 2015, 30 sooty days in 2016

San Antonio-New Braunfels

62 smog days in 2015, 48 smog days in 2016

13 sooty days in 2015, 10 sooty days in 2016


46 smog days in 2015, 22 smog days in 2016


34 smog days in 2015, 20 smog days in 2016


45 smog days in 2015, 20 smog days in 2016

It’s good news that our air is cleaner now than it was last year and dramatically better than it was 30 or 40 years ago. But even one day with unhealthy air is too many. Our report shows that air pollution remains a major threat to our health across Texas.
Air quality improvements have been driven by public health safeguards created by the Clean Air Act and EPA. As Adrian Shelley, formerly head of Air Alliance Houston and now head of Public Citizen's Texas office notes, "Regulations haven't put anyone out of business, prices haven't gone up at the pump, we've just made steady progress reducing ozone pollution. And--crucially--we've done so as the result of federal mandates from the Clean Air Act and the EPA." 
But this data doesn't tell the whole story. Adrian continues, "As for PM2.5, we are continuing to see reductions, and in some sense its the same story as ozone. However, Air Alliance Houston has maintained for years that the rosy PM2.5 picture in the region is the result of cleverly placed monitors--not actual reductions. There are 11 PM2.5 monitors in the region, and only three that ever threatened to put us out of attainment. There have been serious local efforts to reduce PM2.5 near problem monitors. Meanwhile, there are hotspots that are almost certainly violating the PM2.5 NAAQS. If you go out to the 5100 block of Schurmier Rd. in Houston, you'll see five concrete batch plants within a half mile. I've monitored out there in real time and seen values 5-20 times higher than the 24-hour standard. There are PM2.5 hotspots that no one is paying attention to, so the national data on Houston can't really be trusted."

And our clean air success could be at risk with efforts by the Trump Administration and a Texas lawmaker to roll back environmental safeguards. We need to stop these attacks on clean air and instead work to cut pollution further, including through tougher enforcement against big polluters and renewing and fully funding the Texas Emissions Reduction Plan to cut diesel emissions from off-road vehicles. The faster we cut pollution, the sooner dirty air days can become a thing of the past.


Air pollution data for 2015 are from U.S. Environmental Protection Agency, Air Data, Pre-Generated Files, accessed at download_files.html, 18 and 19 January 2017. We used daily summary data for ozone (aka smog) and daily summary data for PM2.5 (aka soot) measured with FRM/ FEM mass methods. Those files include a daily EPA-calculated Air Quality Index (AQI) score from 0 to 500 for each monitoring station and for each pollutant. All the AQI scores in the pre-generated files are based on the current EPA ozone and particulate matter standards; when a standard is tightened, EPA retroactively adjusts the AQI scores for past years. We grouped air quality monitors by corebased statistical area (CBSA) (metropolitan and micropolitan urban areas identified by the federal Office of Management and Budget) and identified the highest AQI score for each day for each pollutant. Per EPA, an AQI score of 51 to 100 is moderate (yellow), 101 to 150 is unhealthy for sensitive groups (orange), a score of 151 to 200 is unhealthy (red), a score of 201 to 300 is very healthy (purple), and a score of 301 to 500 is hazardous (maroon). We counted the number of maximum AQI scores in each category for each CBSA, meaning that if one monitor in a CBSA showed “moderate” or higher pollution and other monitors in the same CBSA did not, we counted the CBSA as having unsafe air that day. Monitors that are not located in a CBSA were grouped by county. Preliminary 2016 smog pollution calculations are based on a version of the pre-generated files for 2016, available at