Reporting Toxic Air Emissions 

We often think of Houston 's "smog soup" as being made from three classes of pollutants: ozone, particulate matter, and air toxics.

• Ozone is the air pollutant that we hear the most about because the 8-county region does not meet the federal health limit for ground-level ozone.
• Recently, we have learned about fine particulate matter because the EPA developed a new standard for these tiny pieces of dirt and soot that mainly come from incomplete combustion. The Houston-Galveston area complies with the federal standard for fine particulate matter, although the region is very close to exceeding the limit.
• We lump most other air pollutants in the Houston region into a category called air toxics . Air toxics are chemical compounds such as toluene and formaldehyde that are known to cause health effects. While we have fairly good data about ozone and fine particulate matter, there are several problems with the data for air toxics.

Monitoring for air toxics in the Houston-Galveston area is primarily concentrated in the area near the Houston Ship Channel. Elsewhere in the region, there are some monitors but not enough to be certain that we fully understand the problem. A major issue is that several important air toxics are rarely or never monitored.

When an air toxics problem is identified (such as high levels of butadiene near Milby Park in east Houston ), it can be difficult to pinpoint the source of the emissions. One reason is that most refineries and chemical plants do very little self-monitoring of their emissions, and instead rely on paper calculations of their emissions when reporting to the state and federal government.

Some air toxics are underreported 4-5x

The EPA relies on self-reports to the Toxics Release Inventory (TRI) to estimate the amount of air toxics released by industry in our region ( http://www.epa.gov/tri/ ). Since releases of air toxics from industries are not widely measured with company pollution monitors, companies use EPA-approved methods of estimating emissions. However, these estimates do not always capture the actual emissions from a company because they may not include leaks and upset emissions. Based on findings by independent researchers and state regulators, it is now widely accepted that emission rates by industry of some air toxics are, on average, at least four to five times greater than reported.

Adjustment factors are used to offset under-reporting

In the Houston-Galveston area, the Texas Commission on Environmental Quality (TCEQ) adjusts the emissions that are reported to the TRI to more accurately reflect emissions that are observed. The TCEQ used information from air toxics monitors on the ground and flown in airplanes to establish "adjustment factors" for ten compounds whose estimates and measurements varied greatly. When these adjustment factors are applied to the TRI data for Harris County , air releases jump 209%, raising it from the second worst to the worst county in the country for toxic air releases. Texas counties, Jefferson and Brazoria, are second and third worst when the adjustment factors are applied. (Table 1.)

Adjustment factors rank Texas on top for toxic air emissions

Similarly, air releases adjusted for the state of Texas increased from 103 million pounds to more than 262 million pounds. This 155% adjustment also changes the state ranking for most air releases, moving Texas from third to first place. Louisiana moved from ninth to second place and Ohio dropped from first to third, reflecting changes made based on emissions from refineries and chemical plants.

Likewise, the adjustment factors resulted in a re-ranking of toxic emissions from facilities. Not surprisingly, seven of the top ten refineries and chemical plants with adjusted toxic emissions are located in Texas and three of those are in the Houston-Galveston area.

Improvements are needed in air toxics reporting

Clearly, the EPA approved methods of estimating toxic air pollutants from refineries and chemical plants are not accurate enough to give the public a good sense of what is in the air they are breathing. Increased air toxics monitoring, either by government or industry is essential to getting a clearer picture of which air toxics are in the air, in what quantities and where they are coming from. This information will empower citizens and persuade industry to take steps to reduce emissions.

Information and tables for this article are from Who's Counting? The Systematic Underreporting of Toxic Air Emissions prepared by the Environmental Integrity Project and the Galveston-Houston Association for Smog Prevention. To view the report, go to http://www.ghasp.org.