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Thesis (M.S.)--University of Hawaii at Manoa, 2007. / Includes bibliographical references (leaves 94-97). / ix, 97 leaves, bound ill., maps 29 cm

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Ambient observations have indicated that ozone formation in the Houston area is frequently faster and more efficient, with respect to NOx consumed, than other urban areas in the country. It is believed that these unique characteristics of ozone formation in the Houston area are associated with the plumes of reactive hydrocarbons, emanating from the industrial Houston Ship Channel area. Thus, accurate quantification of industrial emissions, particularly of reactive hydrocarbons, is critical to effectively address the rapid ozone formation and the consequent high levels of ozone in the area. Industrial emissions of hydrocarbons have significant temporal variability as evidenced by various measurements, but they have been assumed to be continuous at constant levels for air quality regulation and photochemical modeling studies. This thesis examines the effect of emission variability from industrial sources on ozone formation in the HoustonGalveston area. Both discrete emission events and variability in continuous emissions are examined; new air quality modeling tools have been developed to perform these analyses. Also, this thesis evaluates the impact of emission variability on the effectiveness of emission control strategies in the Houston-Galveston area. Overall, the results indicate that industrial emission variability plays a substantial role in ozone formation and that controlling emission variability can be effective in ozone reduction. These results suggest that a quantitative treatment of emission variability should be included in the development of air quality plans for regions with extensive industrial activity, such as Houston.

Using ethnographic research methods, I collaborated with the organization Earthworks to conduct a community assessment on the health issues related to the air quality in Karnes County, Texas, an oil and gas community. The research consisted of in-depth interviews with residents on their experiences and knowledge on the health issues associated to air quality. This research is going to be used to inform the community and develop strategies to empower community members in improving their environmental conditions.

Conventional sources of emissions have been a prime target for policymakers in designing pollution control strategies. However, the evolution of shale gas activities is a growing concern over the impact of unconventional sources on urban and regional air quality. Owing to the development of Barnett Shale production, the fast-growing Dallas-Fort Worth (DFW) metroplex has encountered both types of these emissions. Oil and gas activities result in emissions of ozone precursors, notably volatile organic compounds (VOC). The major objective of this study was to evaluate the spatio-temporal distribution of VOC in order to highlight the influence of unconventional emissions. The study utilized measurements from automated gas chromatography (AutoGC) monitors to analyze the patterns of the total non-methane organic compounds (TNMOC) and relative contributions from marker species of traffic versus oil and gas activities. In this study, data from 2001-2014 was obtained from the Texas Commission on Environmental Quality (TCEQ) for fifteen monitoring sites within the North Texas region. With over a thousand wells in a 10 mile radius, two of the rural sites measured twice as much TNMOC as compared to the urban site in Dallas. Source apportionment analysis was conducted using Positive Matrix Factorization (PMF) technique. The target site located in the urban zone resolved an eight factor model. Natural gas signature was the dominant source of emission with a 52% contribution followed by 31% from two separate traffic-related sources. Considering ethane to be the dominant species in oil and gas emissions, it was observed that the rising ethane/NOx ratio correlated with increasing annual average ozone post-2007. In this period, higher concentration of ozone was found to be associated with stronger winds from the Barnett Shale area – a region that did not seem to contribute to high ozone during 2001-2007. With traffic emissions having flattened over the years, the recent increase in oil- and gas-related emissions has a negative impact on the air quality in this area. Results indicate that the area has failed to observe a declining trend in ozone despite effective reductions in NOx and traffic-related VOC emissions. The findings of the study would be helpful in proper evaluation of the ozone-forming potential of unconventional VOC emissions. Although these emissions may not be strong enough to cause harm through direct exposure, underestimating their potential towards ozone formation could hinder the progress in ozone attainment in growing urban areas. After all, a major portion of the study area continues to be in nonattainment of the EPA designated ozone standards. The study therefore draws the attention of policymakers towards the new influx of emissions that have emerged as a powerful source within the DFW metropolitan area.