1. Big, Beautiful Sky: The State and Future of Texas’ Air
# 25
Big, Beautiful Sky: The State and Future of Texas’ Air
Dr. David Allen
September 5, 2003
Produced by and for Hot Science - Cool Talks by the Environmental Science Institute. We request that the use of these materials include an acknowledgement of the presenter and Hot Science - Cool Talks by the Environmental Science Institute at UT Austin. We hope you find these materials educational and enjoyable.

2. Preserving air quality in Texas
Big, Beautiful Sky?
Preserving air quality in Texas
Professor David Allen
Department of Chemical Engineering
Center for Energy and Environmental Resources
University of Texas

3. Every breath you take…
The Houston region has one of the highest national ozone levels. Asthma prevalence in inner-city Houston school children approaches twice the national average.
Fourteen Americans die every day from asthma, a rate three times greater than just 20 years ago. 673,076 adults and 401, 289 children suffer from asthma in Texas.
Ozone can cause coughing, throat irritation, reduced lung function, and pain when taking a deep breath.
What texas city has one of the highest national ozone levels? What problems does this cause in that city? How many Americans die every day from asthma? Is this more, the same, or less than 20 years ago? Do you think this could be because of more pollution? Why or why not? What health problems can be caused by ozone?

4. Breath of Life?
Scientists have estimated that the number of deaths in the United States associated with air pollution range from 50,000 to 100,000 per year.
While particulate matter is the form of air pollution most prominently linked to premature death, there is increasing evidence that ozone plays a role.
How many deaths in the United States are associated with air pollution?

5. Outline
What are the components of air pollution and how is Texas doing?
What is photochemical smog and how is it formed?
A tale of two cities: Austin
How do we understand air pollution and who sets air quality standards?
A tale of tow cities: Houston
What are scientists and officials doing so we can breath easier?
What can all of us do?
See if you can find the answers to these questions in the talk.

6. Air Quality in Texas cities
Houston, Dallas/Fort Worth and El Paso violate the current ozone standard and Austin, San Antonio and Longview would violate the new ozone standard.
El Paso violates the current particulate matter standard. Houston and possibly DFW would likely violate the new particulate matter standard.
Which Texas cities violate current ozone standards? Which cities would violate the new standards? Which Texas cities violate current particulate matter standards? Which cities would violate the new standards? Why is this important? Who needs to be worried about these standards anyway (who pays the fines)?

7. Air pollutants of concern in Texas
PM10 and PM2.5 - Fine particulate matter suspended in the atmosphere degrades visibility and has been associated with increased rates of mortality
O3 - Ozone at ground level is an irritant, and is associated with increased incidence of respiratory disease and decreased respiratory function
What are the names of air pollutants of concern in Texas? What problems do these pollutants cause?
Hazardous air pollutants – A variety of health impacts associated with exposure to HAPs

8. Air pollutant formation
OZONE = Reactive Organic Compounds *
Oxides of Nitrogen * Sunlight *
Stagnant Air
PARTICULATE = Sulfur Oxides, Reactive Organic MATTER Compounds, Oxides of Nitrogen, Ammonia, Direct emissions + Sunlight + Stagnant Air
What are the components of or leading to ozone and particulate matter?

9. Ozone: Good Up High, Bad Nearby
Why do we want to keep ozone high up in the sky instead of here near by?

10. Understanding atmospheric chemistry is crucial to understanding air pollution
Ozone is formed in the atmosphere by the reactions of volatile organic compounds (VOCs) and oxides of nitrogen (NOx) – Relative effectiveness of VOC and NOx emission reductions varies between cities
Particulate matter is emitted directly and is formed in the atmosphere by the reactions of VOCs, NOx, SOx, and ammonia Relative effectiveness of emission reductions varies between cities
How are ozone and particulate matter formed in the atmosphere? Do these processes occur in exactly the same way everywhere in Texas?

11. A Tale of Two Cities: Austin
Austin: Moderate ozone and fine particulate matter concentrations; air quality dependent on both local and regional sources
Houston: Sees some of the highest ozone concentrations in the United States but relatively moderate particulate matter concentrations; dominated by a mix of local emissions, industrial and urban
How does Dr. Allen describe the general quality of air in Austin? Houston?

12. Austin’s status
All monitors meet the current National Ambient Air Quality Standards – no local regulations in place – only national initiatives (for example, cleaner cars)
The region would be in non-attainment for the new, more stringent NAAQS, due to be implemented in 2004
An Early Action Compact has been initiated
When will new air quality standards be implemented? What is non-attainment?

13. What do we need to know to improve air quality?
Emission inventory development
Air quality modeling
Air quality monitoring
What do we need to know to improve air quality?

14. How do we improve air quality?
National Ambient air Quality Standards (NAAQS) set the threshold for action for many air pollutants
States prepare plans (State Implementation Plans or SIPs) for individual cities
How do we improve air quality? How does the federal government regulate air quality? How does state government regulate air quality?

15. Who sets air quality standards?

16. On-road and non-road mobile sources
Emission inventories
Area sources
Point sources
On-road and non-road mobile sources
Describe, define, and give examples of several sources of emissions in Texas. Which of these do you think contributes most to air pollution? Which do you think contributes least?
Biogenic emissions

17. National sources of VOC and NOx

18. VOC emission inventory (tons/day) for the 5-county region
Biogenics dominate VOC emissions in the 5-county area, but in the urban areas where ozone formation is greatest, anthropogenic sources dominate

19. Anthropogenic VOC emissions (tons/day) for the 5-county region
Travis County dominates anthropogenic VOC emissions, and these emissions are equally divided among on-road, non-road and area sources

20. NOx emission inventory (tons/day) for the 5-county region
On-road and non-road sources dominate NOx emissions

21. Anthropogenic NOx emissions (tons/day) for the 5-county region
Travis County dominates anthropogenic NOx emissions; on-road and non-road sources dominate

22. Along with inventories we need to develop air quality models.
Study the diagram and put into your own words what it means. What elements go into atmospheric chemistry research? Define those elements and describe some of the things you know about them. What are three components of research?

23. Photochemical Grid Modeling: Used in the development of air quality regulations
How are photochemical grid models used? I still don’t understand what this diagram is illustrating.

24. Air quality modeling in Central Texas
Study the maps on slide 23. What geographical area does the map on the left represent? The one on the right? How do you know? What does PPB mean? What information do these illustrations predict about ozone (?) concentrations in central Texas and the South Central United States?
Include both regional and local effects
Identify strategies that will reduce peak ozone concentrations

25. A San Marcos airport station reading
What do the charts on this slide illustrate? How are ozone concentrations, NOx concentrations, and wind direction related. Which component effects a change in the other components? Why might this be?

26. What emission sources contribute to ozone formation?
Evolution of ozone concentrations at a monitor in Austin, over the course of a day, with sources attributed
O3 concentration by type at an Austin Urban Location

27. Sample back trajectories for high ozone episodes in Austin…..

28. Describe how the trajectories of the materials was different between materials released at different starting points. What are some reasons for the difference in trajectory? What does this mean for those trying to set standards for emissions?

29. It’s tempting to blame Houston, but…….

30. Every city in eastern Texas has an impact on at least one other city

31. 32-Hour back trajectories for days with peak 8-hour ozone levels over 75 ppb. 1993-1999

32. So we understand the problem. What do we do?
Main local source is due to vehicles and for on-road vehicles 10% of the vehicles give 50% of the emissions
Regional benefits of emission reductions in other Texas cities
What are the benefits?

33. A Tale of Two Cities: Houston

34. The Houston-Galveston area is a severe ozone non-attainment area
The current State Implementation Plan (SIP) calls for significant NOx emission reductions (approximately 70% of the projected 2007 inventory; 90+% for point sources)
SIP also calls for VOC emission reductions (approximately 25% of the projected 2007 inventory)
Costs and benefits of controls have been estimated to be ~5 billion/yr
By how much (percent) does Houston need to lower its NOx emissions to comply with the current State Implementation Plan? Is this a lot? By how much will they need to reduce their VOC emissions?

35. Ozone formation in Houston is qualitatively different than in most other urban areas

36. Ozone formation in Houston is formed rapidly and efficiently
How is ozone formation in Houston different from ozone formation in most other urban areas? Compare to Austin, slide 25.

37. Rapid ozone formation can be localized, and narrow plumes/high ozone air parcels can persist for long distances.
How do these figures illustrate the nature of ozone formation and transport in Houston? Which direction does the ozone move in these figures?

38. What causes these events? Localized, high hydrocarbon concentrations
What causes the abnormally rapid, high, and concentrated formation of ozone in Houston? Compare the sources of hydrocarbons illustrated in this figure. Which source contributes most to OH reactivity in the atmosphere?

39. Where do we find rapid ozone formation/high hydrocarbon concentrations?
Where on this map are the areas of highest hydrocarbon concentration? What feature are these points linked to?

40. What are these hydrocarbons?
low molecular weight alkenes (propene, ethene and butenes) are a major source of hydrocarbon reactivity for ozone formation.
What are hydrocarbons? What are alkenes, etc.? What is reactivity?

41. Why is Houston so different? Industrial emissions are variable.

42. Texas Air Quality Study (TEXAQS ) Provide scientific basis for air quality management strategies in southeast Texas
What is the Texas Air Quality Study?

43. TEXAQS - 2000 : Sampling Sites
( (
TEXAQS : Sampling Sites

44. TEXAQS and other research programs address key areas of uncertainty
Emission inventories.
Chemical and physical processes in the atmosphere.
Regional air quality modeling.
Slides What is an emissions inventory? How does an emissions inventory give insight into chemical and physical processes in the atmosphere? How can scientists use their knowledge of these preceosses to build models? How do policymakers use models to set emissions standards? How do scientists use emissions inventories to test the effectiveness of emissions standards?

45. TexAQS and other research programs indicate:
Emission inventories: Data from TexAQS suggest that the VOC emission inventory is low by a factor of 3-10
Emissions are variable: Daily variations can change emissions from any single facility by a factor of 100 or more
Air quality models, on which regulations are based, are unable to describe the spatial variability that we see Existing regulatory models have been unable to replicate critical observations

46. How did our improved scientific understanding get incorporated into the regulations?
Accelerated Science Evaluation
TCEQ commissioners to decide whether to stay with existing plan or to craft a “mid-course correction”
For updates, see the web site: (

48. Actions taken by the TCEQ
Based on the data from TexAQS, which indicate that VOC emissions from industrial facilities are underestimated, new rules have been proposed for emissions of reactive hydrocarbons from flares, cooling towers and fugitive sources
What are some of the emissions sources regulated based on data from TEXAQS?

49. Benefits of better scientific understanding to the State of Texas
More effective SIP
More confidence by policy-makers in the decision making process
Demonstration of the value of timely scientific analyses
Demonstration of the value of federal/state scientific partnerships
What are the benefits of understanding atmospheric processes in Texas?

50. What’s next to understand and do?
Our cities are linked; we need to better understand regional ozone formation and transport – across cities and across borders
What new and broader questions still remain unanswered in understanding emission processes in Texas?

51. What’s next…
Need to better understand fine particulate matter and regional haze

52. Second Texas Air Quality Study (STAQS) A New Strategic Texas Air Quality Study
Texas must begin now developing science base for control of 8-Hour ozone, fine particulate matter (PM2.5) and regional haze
STAQS is a five-year field investigation aimed at developing the underlying science for effective control policies
Study will utilize experienced TexAQS 2000 study team;
Leadership provided by Texas universities, TNRCC, Texas Environmental Research Consortium, NARSTO and Southern Oxidants Study
The UT-Austin Center for Energy and Environmental Resources will provide overall study coordination and administration.
What is the STAQS? How is it different from the TEXAQS?

53. Second Texas Air Quality Study (STAQS) A New Strategic Texas Air Quality Study
Develop Science Plan;
deploy/test equipment
Conduct
Develop Attainment Plans
based on best science
Field Study
2003
2004
2005
2006
2007
2008
2009
2010
What are the steps involved in conducting a large-scale air quality study?
Submit Attainment Plans
Develop Operational Plan;
deploy/test equipment
Post Field Study
Data Analysis
and Peer Review
to EPA for Approval

54. What can we do? Keep your automobile well tuned and maintained.
Carpool, use mass transit, walk, bicycle, and/or reduce driving, especially on hot summer days.
During the summer, fill your gas tank during the cooler evening hours.
Participate in your local utility's energy conservation programs.
Seal containers of household cleaners, workshop chemicals and solvents, and garden chemicals to prevent VOC from evaporating into the air. Dispose of them properly.
What can you do to help reduce emissions?

55. Questions? David Allen Allen@che.utexas.edu

56. Dr. David Allen
Dr. David Allen is the Melvin H. Gertz Regents Chair in Chemical Engineering and the Director of the Center for Energy and Environmental Resources at the University of Texas at Austin. Dr. Allen’s research addresses issues related to air quality in Texas. He was a lead investigator in one of the largest and most successful air quality studies ever undertaken: the Texas Air Quality Study ( His current work is focused on using the results from that study to provide a sound scientific basis for air quality management in Texas. Dr. Allen also serves as the Chair of the Texas Council on Environmental Technology(TCET), which was established by the 77th Legislature. TCET is charged with encouraging the development, demonstration, certification and deployment of novel technologies for cost-effectively reducing emissions to air, water and land in Texas. At the national level, Dr. Allen serves on the Science Advisory Board of the EPA, dealing with issues of air quality modeling and cost-benefit analysis of the Clean Air Act. He also serves on the National Research Council’s Board on Environmental Studies and Toxicology. Dr. Allen received his B.S. degree in Chemical Engineering, with distinction, from Cornell University in His M.S. and Ph.D. degrees in Chemical Engineering were awarded by the California Institute of Technology in 1981 and He is the author of4 books and more than 150 technical papers. He has held faculty appointments at UCLA and the California Institute of Technology; he joined the University of Texas in 1995.