by SEAN BATURA
The Austin Metropolitan Statistical Area, which include San Marcos, barely avoided violating federal ozone air quality standards this year, and the city itself experienced at least five days with unhealthy ozone levels.
On 10 days in 2011, ozone rose to levels regulators consider unhealthy for sensitive groups, such as people with asthma, children, senior citizens, and people who work outdoors, the Capital Area Council of Governments reports.
With the end of the ozone season on Oct. 31, the area’s ozone “design value” of 75 parts per billion (ppb) maintained compliance with the current federal ozone standard of 75 parts ppb for a third year in a row, according to the CAPCOG report.
A design value is calculated as the average of the region’s fourth highest eight-hour ozone level measured during the year, which is then averaged over three years. The Austin MSA’s design value was 74 ppb in 2010.
“But compared to other parts of the state, we’re in a much better position,” said Andrew Hoekzema, CAPCOG air quality program specialist. “Dallas and Houston, in particular, have much worse air quality than our area. We’re kind of right at the cusp of the standard right now. The area (in the Austin MSA) that has the highest three-year average is in Travis County, and if we had had one extra bad day, it would have put us over it.”
The highest ozone days for San Marcos were Aug. 28 (77ppb), Sept. 7 (86 ppb), Sept. 9 (78 ppb), Sept. 11 (82 ppb), and Sept. 24 (79 ppb), said Hoekzema.
CAPCOG, established by the Texas Legislature in 1970, operates air quality monitors in the Austin MSA and is a voluntary association of more than 90 member cities, counties school districts, chambers of commerce, non-profit agencies, and other organizations.
The previous federal ozone standard, implemented in 1997, was 84 ppb. In 2008, the administration of then-President George W. Bush set the ozone standard at 75 ppb, though a federal Clean Air Scientific Advisory Committee had recommended 60-70 ppb. The World Health Organization recommends 51 ppb.
Ozone levels as low as 40 ppb can cause health effects in susceptible populations, according to a 2008 article appearing in Environmental Health Perspectives, which is a monthly journal of peer-reviewed research published by the National Institutes of Health. According to the article, “a great deal” of research suggests 80 ppb is too high to adequately protect the health of many people.
Ozone in the upper atmosphere affords protection from ultraviolet radiation, though at ground level, it is a harmful air pollutant and a primary constituent of urban smog, states a current NIH fact sheet. Ozone is produced when air pollutants from automobile emissions and manufacturing operations interact with sunlight. Health effects linked with ozone include premature death, low birth weight, heart attack, asthma, bronchitis, and other cardiovascular problems and respiratory diseases.
Hoekzema said half of the amount of ozone contributed by the MSA is from on-road vehicles, 20-25 percent is from non-road sources like construction and agricultural equipment, and the remaining 25-30 percent is from industrial sources such as power plants, cement kilns, lime kilns, and oil/gas production equipment.
“That 2008 standard of 75 ppb could very well get ratcheted down lower to 60-70 ppb,” Hoekzema said. “That’s what the scientific advisory committee had recommended. So if that’s the case, that would probably happen in, say, 2014, and EPA would issue a new round of designations for the new standard in 2016. So if by that time we’re not at that level, we would face a nonattainment designation.”
Hoekzema said it is unlikely the federal government will loosen the ozone standard.
Ozone formation is a complex process affected by weather, topography, altitude, and other factors. Pollution emitted in one area may cause ozone formation somewhere far away.
Hoekzema said the highest ozone days in the Austin MSA are usually in late August or early October. During those months, there is low wind and high sunlight, which is conducize to the formation of ozone, and the wind is usually the wind carries non-local emissions from the northeast.
“Our big deal is we get a lot of transport from outside of our region coming into our region,” Hoekzema said. “And personal vehicles, trucks and stuff, are the lion’s share of the emissions. Construction equipment, for instance, is a pretty big source of emissions as well, in our region.”
Hoekzema said a cement plant in Buda is the largest point source in the Austin MSA for nitrogen oxide. Nitrogen oxide and volatile organic compounds are precursors to ozone. Nitrogen oxide forms in the presence of nitrogen, oxygen, and very high temperatures, so any kind of combustion will create nitrogen oxide. Coal and cement plants produce the most nitrogen oxide emissions on a per point source basis, Hoekzema said.
“We’re in a precarious spot right now,” Hoekzema said. “Vehicle standards and…engine standards are supposed to reduce emissions significantly over the next couple of years and as long as the background levels at least don’t go up, we should be able to continue moving downward. But meterology plays such a large role in it. If we have another year next year like we did this year, we could very well go above the standard for a three-year average. Over the long-term, the trends are looking favorable for gradual progress.”
Once an area fails to attain the federal ozone standard, the government may mandate vehicle inspection and maintenance programs. Travis and Williamson counties have voluntarily implemented vehicle inspection and maintenance.
“Once an area is designated ‘nonattainment,’ a state is required to develop a plan to bring the area into attainment,” Hoekzema said. “This plan must be approved by EPA and any regulations in the plan become federally enforceable. Once the area attains the standard, the state must develop a ‘maintenance plan’ to show that the area will continue to attain the standard for a period of 10 years.”
If the Austin MSA were to run afoul of the ozone standard, the Texas Commission on Environmental Quality would have to develop rules for all major sources of nitrogen oxides and volatile organic compounds (defined as emitting more than 100 tons per year) in the area, which could involve expensive equipment installation, Hoekzema said.
Additionally, TCEQ would create rules for any smaller sources such as lithographic printing presses and facilities that use industrial solvents. For example, a print-shop owner might be required to use lower-solvent content inks and cleaning supplies.
Hoekzema said the only large source of nitrogen oxide in San Marcos as far as he knows is the Hays Energy Project, which is a gas-operated plant less than five miles south of the outlet malls.
Once an area is designated nonattainment, all regional transportation plans must be approved by the federal government, and all regionally significant projects must be included in the plans in order for construction to proceed, Hoekzema said.
“If the state does not submit an ‘attainment demonstration’ plan showing how it will get an area into attainment, if the plan is rejected and not corrected in a timely manner, or if the region’s transportation plan cannot be shown to conform to the plan, the federal government may withhold transportation funding,” Hoekzema said. “However, this is very rarely used and when it has been used (Atlanta was one case), it was only restricted while the state corrected the problem.”
Transportation projects in Hays County were recently cleared to receive about $10.859 million in federal funds for the next three years. About $4.28 million of these funds are for Texas State University and City of San Marcos projects. A study assessing how to move freight trains off of tracks located in San Marcos was recently awarded $8 million in federal transportation funds.
» Interactive: Areas exceeding EPA ozone air quality levels [Texas Tribune]