Date of Award
Civil and Environmental Engineering
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Investigations of increasing ground-level ozone (GLO) concentrations in Windsor during 1996-2015 were conducted by statistical and regional transport analysis. Long-term GLO trends at various percentile levels were identified in Windsor during study period. Increasing 25th percentile level GLO concentrations (0.67 ppb/year) was observed in Windsor suggesting an increase of background GLO. Whereas, peak GLO concentrations were decreased (-0.41 ppb/year) due to emission reductions of NOx and VOC. Seasonal GLO trends were detected by Mann-Kendall test in Windsor during the study period. Increasing GLO concentrations in non-smog season were twice much as those in smog season. GLO concentrations on weekends (33 ppb) were significantly higher than those on weekdays (30 ppb) due to a decrease of NO titrations. Backward air trajectories were run by HYPSLIT model in smog season during 1996-2015. It was found that the highest 8-hour max GLO concentration (57 ppb) in Windsor were associated with air trajectories transported from the south. In the south of Windsor, there are industrial states of Ohio and Indiana. In addition, frequency of southerly flow (160°-200°) has increased 30% in Windsor in smog season during the study period. It was found that increasing GLO concentrations in Windsor during 1996-2015 are attributed to, 1) the increase of background GLO concentrations, 2) the decrease of NO titrations, and 3) the increase of regional transport GLO from the south of Windsor.
Zhang, Tianchu, "Long-term trend of ground-level ozone through statistical and regional transport analysis" (2016). Electronic Theses and Dissertations. 5880.