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Air Quality Monitoring and Data Analysis Research Reports

Reports from TCEQ-contracted projects on air quality monitoring and data analysis.

Reports from air quality monitoring and data analysis research projects are presented below by the year the report was delivered. Some reports have companion data files in various formats.

Contact us at about these or other TCEQ-supported research projects.

Ozonesonde Launches in 2023: Final Report - During the period 26 May - 17 October 2023, a team of researchers from the University of Houston, St. Edward's University, Trinity University, and the University of Texas at El Paso carried out a total of 60 ozonesonde launches in El Paso, San Antonio, and Houston, Texas (26 launches from El Paso, 24 from San Antonio, and 10 launches from Houston). This effort had the primary purpose to sample, characterize, and explain ozone and meteorological features in the boundary layer, the lower free troposphere (LFT), and the upper troposphere/lower stratosphere (UTLS) in these regions. Launches were targeted at days when ozone was expected to exceed the level of the Federal standard to inform and improve our understanding of conditions under which such exceedances could occur. The data collected from San Antonio and El Paso builds on past ozonesonde campaigns in 2017, 2019, and 2020. The data collected from Houston builds upon the 2021 TRacking Aerosol Convection ExpeRiment - Air Quality (TRACER-AQ) and 2022 TRACER-AQ2 campaigns (Jensen et al., 2022; Judd et al., 2021). Data from this project support analyses of conditions associated with high ozone events in these regions. (March 2024)

Source apportionment by Positive Matrix Factorization at Houston North Wayside - This project uses PMF analysis to determine possible source profiles that may be contributing to particulate matter pollution at the Houston North Wayside monitoring site. (March 2024)

Analysis of 2021 TRACER-AQ Field Study Data - The University of Houston analyzed the 2021 TRACER-AQ field study data from the greater Houston area. Key results showed the importance of meteorological conditions and volatile organic compounds for ozone formation. The unique boat, mobile laboratory, and other platforms allowed for data collection in places previously not frequented, which will improve the understanding of air quality science and planning. (May 2023)

2023 Ambient VOC Monitoring in El Paso, TX - The University of Texas at Austin continued monitoring of volatile organic compounds at the Delta Drive monitoring site in El Paso, Texas and analyzed the data to estimate source types affecting the monitor. The data is expeected to be included in air quality planning efforts for the El Paso area. (November 2023)

2022 TRACER-AQ 2 Air Quality Field Campaign in Houston - In August and September of 2022, the University of Houston, Baylor University, St. Edward's University, and FluxSense monitored air quality and emission fluxes from mobile vehicles, boats, balloons, a drone, and fixed surface sites. This 2022 field study was a follow-up to the 2021 TRACER-AQ campaign that characterized air quality throughout the Houston region. The collected data are expected to improve air quality science and inform future air quality decisions. (July 2023)

Houston Soil Moisture Monitoring in 2021 and 2022 - The Bureau of Economic Geology from the University of Texas at Austin monitored soil moisture and meteorological parameters at four sites in the Houston area in 2021 and 2022. The monitoring and development of near real-time maps of soil moisture supported the Tracking Aerosol Convection interactions ExpeRiment (TRACER) field campaign and is expected to contribute to weather and air quality modeling. (January 2023)

2021 San Antonio Field Study Analysis - This report presents the analysis of 2021 San Antonio field study air quality data and compares those with 2017 San Antonio field study. The report also includes modeling analysis to complement or validate the observational data of ozone and its precursors. (May 2023)

Emission Flux and Air Quality Data Collection for TRACER-AQ 2 Field Campaign in Houston - In support of the 2022 TRacking Aerosol Convection interaction ExpeRiment - Air Quality (TRACER-AQ 2) field study in Houston, Fluxsense characterized emission fluxes and ambient pollutant concentrations near the Houston Ship Channel, Baytown, Channelview, and other areas. HRVOCs (ethylene and propylene) were the focus compounds, but emissions of other compounds like formaldehyde, nitrogen dioxide, and alkanes were also measured. These additional compounds are useful for historical comparison and examining trends for air quality within the Greater Houston region. (March 2023)

2021 Air Quality Data Collection for the TRACER-AQ Field Campaign in Houston - As part of the 2021 TRacking Aerosol Convection interaction ExpeRiment - Air Quality (TRACER-AQ) field study in Houston, the University of Houston, Baylor University, and St. Edward's University monitored air quality from mobile vehicles, boats, balloons, a drone, and fixed surface sites. The collected data will combined with NASA aircraft data, modeling, and other data to improve our understanding of how pollution varies and forms across the Houston area. The results are expected to contribute to improved air quality planning for many years. (November 2022)

Oxygenated Volatile Organic Compound (OVOC) Sampling for Biomass Burning Tracers - This project tested a sampling instrument for eight oxygenated VOC tracers of biomass burning in Houston, Texas during August and September 2021. It also compared the results of this sampling technique to results from the UH/Baylor (BC)2 biomass burning sampling project. (August 2022)

Ambient VOC Monitoring in El Paso, TX - This project monitored ambient levels of volatile organic compounds (VOCs) that contribute to the formation of ozone at the Delta Drive monitoring site in El Paso, Texas in 2021 and early 2022. (June 2022)

Applying Machine Learning Techniques to Track Wildfire Smoke Plumes - Phase II - In this project, AER continued developing a machine learning technique to track wildfire plumes from satellite data. (June 2022)

Meteorologically Corrected Ozone, SO2, and PM2.5 Trends - This project used Generalized Additive Models to estimate meteorologically corrected ozone, SO2, and PM2.5 Trends for several Texas urban areas.

Data Analysis Meteorology and Air Quality Analytic Support - AER staff provided targeted analytical support to the Air Modeling and Data Analysis Section to investigate the meteorology associated with a set of high PM2.5 days at several monitors in Texas. (April 2022)

Operationalizing Exceptional Event Tools - In this project AER made the Stochastic Time Inverted Lagrangian Transport model with an integrated Aerosol Simulation Program (STILT-ASP) modeling tools for wildfires and the exceptional event screening tool for stratospheric intrusions available to TCEQ staff via docker containers. (June 2022)

Black and Brown Carbon (BC)2 Monitoring in El Paso and Houston - The University of Houston and Baylor University conducted sampling in the El Paso and Houston areas to identify the influence of wildfires and dust events on urban air quality. This project continued and expanded on monitoring during the 2019 ozone season in El Paso . (July 2021)

Ozonesonde Launches in San Antonio and El Paso - The University of Houston conducted a series of ozonesonde launches in San Antonio and El Paso during 2020 to measure, characterize, and explain differences in ozone concentrations in the lower part of the atmosphere. Ozonesonde launches were conducted on days expected to be above the federal health standard for ozone. The data analyses focused on conditions associated with high ozone events in these two regions. (June 2021)

Houston 2018 Exceptional Event Analysis - This report, provided by Ramboll, analyzes July 26-27 and August 23-24, 2018, ozone exceedances at the Houston area Aldine and Bayland Park monitoring sites to find if wildfires outside of Texas caused the exceedances. (August 2019)

Uncertainty Analysis and Improvement of STILT-ASP for Determining O3 Formation from Biomass Burning - This project performed a global uncertainty analysis of the current STILT-ASP model via two different approaches (emulation and complex step). It also updated parameters for plume rise and mixing parameterizations. (June 2019)

Separation of Poor Air Quality Events in El Paso, Texas Based on Dominant Sources of Emissions - This project uses clustering algorithms, WRF-STILT, and other tools to separate poor air quality events predominantly influenced by Mexican emissions from those predominantly influenced by US emissions. (June 2019)

An Investigation of Background Ozone and Particulate Matter Levels in the Houston/Galveston/Brazoria Metropolitan Area - The purpose of this project was to better understand continental background levels of ozone, NOx, and PM2.5, transported into the Houston area. Utilizing daily PM2.5 speciation filters as well as hourly measurements of ozone, NOx, and PM2.5. Seven primary source categories of PM2.5 were identified: crustal, industrial, gasoline combustion, incineration, regional aerosols, marine aerosols, and biomass burning. Clustering of HYSPLIT back trajectories was also performed with source with trajectory pathways corresponding to known areas of PM2.5 source regions. (July 2018)

Analysis of Foreign and Transport Contributions to PM2.5 Concentrations at the Houston Clinton Drive, Galveston 99th Street, and El Paso Chamizal Monitors - This report, provided by the University of Texas at Austin, describes transported PM2.5 to Galveston 99th Street monitor. It also describes source apportionment via Positive Matrix Factorization (PMF) to Galveston 99th Street monitor, El Paso's Chamizal monitor, and Guadalupe National Park. (June 2018)

Assessment of the Exceptional Event Rule's "Q/D" Guidance - The purpose of this project was to create a technical assessment of the “Q/D” criteria developed by the US EPA as part of guidance for its Exceptional Events Rule (EER). Assessment of the guidance was achieved through reviews of EPA evidence used in construction of the guidance, a review of the literature surrounding biomass burning plumes, and photochemical modeling (STILT-ASP; CAMx) of biomass burning plumes. Additional project materials available on request. (June 2018)

El Paso Ozone and PM2.5 Background Totals Trend Analysis - The purpose of this project was to determine the effects of meteorology on local and regional background trends in O3 and PM2.5 in El Paso, Texas. O3 and PM2.5 events in the urban area changed with afternoon mean temperature, daily average wind speed, and synoptic type. These predictors were chosen as they had been shown to be important in previous work. After meteorological adjustment via a GAMs model fit to total and background O3 and total PM2.5, no trends in pollutant metrics between 2007-2016 were observed to be significant at a 95% confidence level. The adjusted trend in total O3 for El Paso sites only was -0.07 ± 1.31 ppb/yr, while the regional background trend was 0.45 ± 0.45 ppb/yr. The adjusted trend in total PM2.5 was -0.340 ± 2.063 μg/m3/yr. Additional material available upon request. (June 2018)

2016-2017 Biogenic VOC Monitoring - This report, provided by The University of Texas at Austin, documents the monitoring of surface isoprene concentrations at the Big Thicket National Preserve north of Beaumont. A fast-response isoprene, photosythentically active radiation (PAR), and meteorological instruments were placed at the Big Thicket Radio Tower Site from March 2016 through October 2017. The isoprene instrument was placed in the Big Thicket to measure biogenic isoprene emissions from a forest that biogenic emission models predict to have elevated isoprene emissions. The collected data is available upon request. (February 2018)

Upper Air Wind Measuring at Two Locations in San Antonio - This report describes measurements made of the structure and wind profiles of the lower atmosphere during May 2017 in San Antonio. The San Antonio Field Study 2017 studied the meteorological and chemical features of the atmospheric environment of San Antonio to learn the causes of high ozone in the area. (December 2017)

Eagle Ford Shale Baseline Monitoring Study - This report, provided by University of Texas at Austin, documents the project to obtain important baseline measurements of trace gas pollutants that may result from oil and gas activity in the Eagle Ford Shale (EFS) formation area south and east of the San Antonio metropolitan area. The data collected at Floresville will add to the TCEQ’s current knowledge and inform future air quality planning efforts related to the San Antonio area. (November 2016)

An Analysis of Biomass Burning Impacts on Texas - This report, provided by Atmospheric and Environmental Research, Inc., documents the further development of a trajectory-based modeling tool coupled with a chemistry mechanism to assess the impact of wildfire events on ozone and/or PM2.5 without developing a SIP-quality modeling episode. The core of this tool is the Stochastic Time Inverted Lagrangian Transport (STILT) model with an integrated chemical mechanism, the Aerosol Simulation Program (ASP). STILT is somewhat analogous to HYSPLIT while the ASP mechanism focuses on aerosol and ozone formation from fires. (June 2016)

Source Apportionment of Fine Particulate Matter at Big Bend National Park - Task 2 – PMF Analysis of Big Bend National Park IMPROVE Aerosol Data - This report, provided by Atmospheric and Environmental Research, Inc., documents the project to perform a source apportionment of fine particulate matter (PM2.5) in Big Bend National Park for 2011 – 2014. The project updated TCEQ’s knowledge on sources of fine particulate matter impacting visibility in the park. (June 2016)

Conceptual Model of Ozone Measurements at Palo Duro Canyon - In this project, Atmospheric and Environmental Research, Inc. developed a conceptual model of ozone causes and formation at the U.S. Environmental Protection Agency Clean Air Status and Trends Network monitoring site located just outside of Palo Duro Canyon State Park in Randall County, Texas. (June 2016)

Investigating the Impact of Meteorology on O3 and PM2.5 Trends, Background Levels, and NAAQS Exceedances - This report, provided by Atmospheric and Environmental Research (AER), uses General Additive Models to investigate the impact of meteorology on Ozone and PM2.5 trends in several Texas metropolitan areas. (Additional files ) (August 2015)

Estimation of On-road Mobile Source Emissions Associated with Oil and Gas Development in the Eagle Ford Shale Area - This report, provided by Texas Transportation Institute (TTI). When oil and gas drilling activities increase in an area such as the Eagle Ford Shale formation the drilling rigs are not the only source of new emissions. Heavy-duty diesel trucks drive to and from the drill sites delivering equipment, water, drilling mud, and other supplies. Similarly, economic activity associated with the housing, food, traqnsportation, and entertainment neds of oil field workers and their families increases. This project aims to estimate the overall mobile source impact of oil and gas development in the Eagle Ford Area. (Appendix D ) (August 2015)

Eagle Ford Shale Mobile Monitoring Study - This report, provided by University of Texas at Austin, summarizes the results of a mobile air sampling study in Eagle For Shale area. The researchers outfitted a Chevrolet Suburban with equipment for sampling methane, total hydrocarbons, and nitrogen oxides (NOx), then made a total of twelve trips that included upwind and downwind transects of the Eagle Ford Shale (EFS) oil and gas producing region of South Texas. Speciated hydrocarbon canister samples were also taken at upwind and downwind locations chosen to be representative of overall air quality before and after air passes through the EFS region. (August 2014)

Resources for Analyzing The Impacts Of Exceptional Events on Downwind Pollutant Levels - This annotated bibliography, provided by URS, lists sources of information relevant to the analysis of exceptional events and tools useful for analyzing the causes of exceptional events. This bibliography provides TCEQ staff and external stakeholders with a place to begin their analysis of exceptional events. (August 2014)

Analysis of Wildfire Impacts on High Ozone Days in Houston, Beaumont, and Dallas-Fort Worth during 2012 and 2013 - This report, provided by Environ, assesses whether high ozone days in 2012 in 2013 in Houston, Beaumont, and Dallas-Fort Worth areas may have been influenced by wildfire emissions, and whether any days contributing to the design value might be excluded from comparison with the National Ambient Air Quality Standard for ozone under the Exceptional Events Rule. (July 2014)

Ozone Precursors and Toxic Chemical Compound Monitoring Continuation - This report, provided by University of Texas at Austin, documents a multi-year (2010 – 2013) monitoring and analysis project in the Barnett Shale. The project deployed auto GC instruments at Eagle Mountain Lake in the town of DISH, and an NOx monitoring at Parker County, Keller and Eagle Mountain Lake. The project's purpose was to characterize the emissions of the Barnett Shale with respect to ozone formation, in particular Eagle Mountain Lake; the ozone design value monitor at the time of equipment deployment. (March 2013)

Interaction of Downward Ultraviolet Radiation with Air Pollution and Clouds - This report documents the work, conducted by the NOAA Climate Prediction Center, to explore the relationship between incoming ultraviolet radiation, clouds, and aerosols. (December 2010)

An Advanced Database Resource for Ambient Atmospheric Data - This report, provided by University of Houston and Portland State University, documents a Geographic Information System (GIS)-based, web accessible database that merges and makes available the data from the TexAQS II air quality study. This database gives the study participants access to all of the data via an intuitive graphical user interface and facilitates data upload, merging, download, visualization, and statistical analysis. This project allows a quicker and integrated analysis of the study's diverse array of data. This database, with its integral GIS capabilities, also allows integration of the chemical and physical data collected in TexAQS II with census, traffic, topological, and epidemiological data. (March 2009)

Effects of Meteorology on Pollutant Trends - In order to accurately show that ozone control strategies are effective, one must separate (or control for) the meteorological influences present in ozone, VOC, and NOx trends. This report, developed by University of Texas - Austin, presented an analysis of the ozone, NOx, and VOC trends in all nonattainment and near nonattainment areas in Texas using regression based methods to show ozone trends without meteorological influences. (December 2008)

Comparison of Solar Occultation Flux (SOF) Measurements to the 2006 TCEQ Emission Inventory and Airborne Measurements - The purpose of this work was to offer a "state of the science" comparison between the SOF data and the TCEQ emission inventory, in order to see how well the TCEQ inventory reflected "true" emissions, across some 14 "sectors" within HGA. This was done for three classes of VOCs (ethene, propene, and alkanes), as well as NO2 and SO2. (November 2008)

Exploratory Source Apportionment of Houston's Clinton Drive Auto-GC 1998-2001 Data - This project was an exploratory investigation into the use of receptor-based models with Auto GC data in the Houston Ship Channel area. STI developed a database of Auto-GC data from the Clinton Drive site (1998 - 2001) for use in Positive Matrix Factorization. Fifteen different source types were found by their composition fingerprints, temporal characteristics, and wind-direction dependencies. (May 2003)

TexAQS 2000 Phase II, Analysis of NOAA Data - This final report developed by the National Oceanic and Atmospheric Administration (NOAA) Aeronomy Laboratory provides an analysis of data taken during the TexAQS 2000 field study to determine the efficiency of production of ozone and fine particles from urban and industrial plumes in the Houston area. (March 2003)

TexAQS 2000 Wind Profiler and GPS Sounding Quality Control - This report, from NOAA’s Environmental Technology Laboratory, provides information on the quality control of wind profiler and GPS sounding data collected during the TexAQS 2000. (February 2003)

Acquisition, Review, and Analysis of AutoGC VOC Data in the Houston Area 1998 - 2001 - This report from Sonoma Technology Inc. provides the final results of analyses structured to explore overall characteristics of the auto-GC data, episode versus non-episode differences, composition/concentration differences with respect to wind quadrant, and combinations of these investigations. (July 2002)

Baylor Aircraft Flight Summary Data: 1997 - 2001 (MS Excel) - An MS Excel spreadsheet file containing summary information on Baylor aircraft flights for the years 1997 - 2001. (April 2002)

Preliminary Analyses of Houston Auto-GC 1998-2001 Data: Episode/Non-Episode Differences - This report, from Sonoma Technology Inc., provides the preliminary results of analyses structured to explore overall characteristics of the auto-GC data, episode versus non-episode differences, composition/concentration differences with respect to wind quadrant, and combinations of these investigations. (March 2002)

Summary of Data Validation of 2001 Auto-GC Data - This report, from Sonoma Technology Inc., discusses validation of the auto-GC data collected during 2001 in Houston area. (March 2002)

Assistance with Twin Otter Data Manipulation, Quality Checking, and processing for the TexAQS 2000 Air Measurement Data Set - This report, from Sonoma Technology Inc., provides the information on the improvement of the quality and confidence level of the Baylor University Twin Otter air measurement data set and preparation of a self-consistent data set for the flights conducted during TexAQS 200 for subsequent analysis. (October 2001)

Characterization of Auto-GC Data in Houston - This report, from Sonoma Technology Inc., provides the extended outline of analyses of auto-GC data to identify relationship of VOCs to ozone events in Houston, blending the analyses (and their documentations) previously performed by TCEQ with more recent analyses. (August 2001)

Airborne Pollution Monitoring Services - Year 2000 Project Summary - This report, from the Central States Air Resources Agencies (CenSARA) and Baylor University, provides information on the aircraft flights and measurements taken during 2000. (August 2001)

Analysis of Year 2000 Air Quality Data Collected by the Baylor University Aircraft - This report from Sonoma Technology Inc. characterizes and reviews the Baylor Aircraft flights and addresses some technical questions regarding ozone pollution in the Houston-Galveston area. (July 2001)

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