The Texas Air Quality Study: State of the Science of Ozone and Particulate Matter formation in Texas and Implications for Air Quality Policy
Abstract
The Texas Air Quality Study (TexAQS) was performed during August and September of 2000; approximately 300 investigators from around the world made measurements of air pollutant concentrations and meteorological variables in southeast Texas. Five aircraft were deployed; five major ground chemistry sites were established and approximately 20 peripheral sites were established for collecting additional meteorological and chemical data. The scope, goals and preliminary results are available at the study web sites (www.utexas.edu/research/ceer/texaqs and www.utexas.edu/research/ceer/texaqsarchive). This presentation will provide an overview of the main findings from the study and will describe the role that ongoing data analysis activities are having on the development of air quality policy in the State of Texas. Some of the major findings are: Finding 1. Almost without exception, air parcels with very high ozone concentrations, observed by aircraft during the Texas Air Quality Study, had back trajectories that indicated a substantial contribution of emissions from industrial source regions. These air parcels also had chemical compositions that were representative of industrial sources, rather than typical urban sources. Finding 2: The rate of ozone production in and around the industrial source dominated areas in Houston can be very high, commonly exceeding 50 ppb/hr, and at times approaching instantaneous rates of 200 ppb/hr. Finding 3: The efficiency of ozone production in and around the industrial source dominated areas in Houston can be very high, ranging from 10-20 molecules of ozone per molecule of reacted NOx. Finding 4. Ozone production in the Houston urban plume was found to be slower and less efficient than in the composite industrial plume from the Ship Channel region and in plumes from isolated petrochemical facilities. Finding 5. The high rates and high efficiencies of ozone production in the industrial plumes are driven by high concentrations of reactive hydrocarbons in the presence of NOx. Finding 6. Industrial hydrocarbon emissions are significantly underestimated. Finding 7: The methods and data that current regulatory models use to calculate ozone formation in industrial plumes may not be adequate to explain the rapid and efficient ozone formation observed in industrial plumes.
- Publication:
-
AGU Spring Meeting Abstracts
- Pub Date:
- May 2002
- Bibcode:
- 2002AGUSM.A21C..01A
- Keywords:
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- 0305 Aerosols and particles (0345;
- 4801);
- 0365 Troposphere: composition and chemistry