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Advances in Air Pollution Simulations for the United States: Ozone and Ultrafine Airborne Particulate Matter.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Advances in Air Pollution Simulations for the United States: Ozone and Ultrafine Airborne Particulate Matter./
Author:	Venecek, Melissa A.
Published:	Ann Arbor : ProQuest Dissertations & Theses, : 2018,
Description:	328 p.
Notes:	Source: Dissertations Abstracts International, Volume: 80-09, Section: B.
Contained By:	Dissertations Abstracts International80-09B.
Subject:	Aeronomy. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10982174
ISBN:	9780438930766

Advances in Air Pollution Simulations for the United States: Ozone and Ultrafine Airborne Particulate Matter.
Venecek, Melissa A.

Advances in Air Pollution Simulations for the United States: Ozone and Ultrafine Airborne Particulate Matter. - Ann Arbor : ProQuest Dissertations & Theses, 2018 - 328 p.

Source: Dissertations Abstracts International, Volume: 80-09, Section: B.

Thesis (Ph.D.)--University of California, Davis, 2018.

This item must not be added to any third party search indexes.

Air pollution throughout the United States has changed dramatically over the past 50 years in response to numerous initiatives to protect public health. The improved efficiency of motor vehicles and adoption of stricter emission policies on coal-fired power plants are two of the reasons concentrations of criteria air pollutants have decreased. Despite nationwide reductions in most pollutant emissions, many urban regions throughout the United States still exceed unhealthy levels of criteria air pollutants. The underlying causes of these exceedances are difficult to determine as they may be the result of unidentified sources, certain meteorological conditions or changes to ambient pollutant concentrations that may alter the formation of secondary pollutants. In order to develop plans that manage these air pollution episodes, accurate tools that are used to resolve the underlying sources and chemical pathways are required. This dissertation describes three studies that improve our understanding of the causes of modern air pollution problems and provide insights that are useful for the development of the next generation air pollution abatement strategies. The first study explores the effectiveness of historical ozone control strategies by updating the calculation of the Maximum Incremental Reactivity (MIR) scale that predicts ozone production from volatile organic compounds (VOCs). Inputs to the MIR calculations were modernized from 1988 atmospheric conditions to 2010 conditions by accounting for changes in meteorology, emission rates, and background concentrations. The calculations show that the median MIR values across thirty nine cities in the United States decreased by approximately 20% due to the impact of emissions control programs on the atmospheric composition and updates in meteorological variables including temperature, humidity, and boundary layer height. Although the absolute MIR values decreased, the sorted MIR rank of each specific VOC did not change strongly compared to the original rankings calculated using 1988 conditions. These findings indicate that past decisions about ozone control strategies remain valid today and the MIR scale continues to provide relevant guidance for policy makers. The second study evaluates an updated version of the SAPRC chemical mechanism for the prediction of ambient ozone and peroxy-radical concentrations. The SAPRC16 mechanism represents more compounds explicitly and includes a new lumping scheme to improve toxics and SOA precursors compared to the previous SAPRC07 and SAPRC11 mechanisms. SAPRC16 was applied under ambient conditions in cities spanning the United States in order to determine if the improved performance observed during the simulation of smog chamber experiments translated to the real atmosphere. Concentrations of ozone, hydroxyl radical (OH) and hydroperoxyl (HO2) radical were predicted with SAPRC16 and SAPRC11, and compared to measured values. It was generally observed that SAPRC16 predicts slightly lower ozone concentrations than SAPRC11 in NOx rich urban centers. Predictions from SAPRC11 are in better agreement with the measurements in the western United States; however, SAPRC16 outperforms SAPRC11 in some eastern and southern U.S. cities. Ozone concentrations predicted by SAPRC16 and SAPRC11 diverged more as emissions decreased suggesting that the two mechanisms will predict different outcomes from increasingly stringent future emissions control programs. A box model analysis showed that the SAPRC16 mechanism quenches ozone production earlier than SAPRC11 as NOx concentrations increase (yielding decreased VOC/NOx ratios). This could be caused by more detailed HO2+RO2 reactions and RO2 isomerization reactions in SAPRC16 that compete with the HO2+NO reaction. The predictions of OH and HO2 were also evaluated for the two mechanisms using measurements from the CalNex field study in Pasadena. SARPC11 and SAPRC 16 prediction of OH are similar and within EPA criteria for mean fractional error (<0.75). However, SAPRC16 largely under predicts HO2 leading to the conclusion that further analysis of the HO2+RO2 reactions and RO2 isomerization reactions is needed before the SAPRC16 chemical mechanism is widely adopted. The final study described in this dissertation investigates the predicted concentration of PM0.1 in thirty-nine urban regions throughout the U.S. during summer pollution events in 2010. PM0.1 is a subset of PM2.5 that has been measured to have high toxicity and has been found to be associated with Ischemic Heart Disease (IHD) mortality in recent epidemiological studies. Artificial source tags were used to track contributions to primary PM0.1 and PM2.5 from fifteen source categories. On-road gasoline vehicles, diesel vehicles, and food cooking significantly contributed to regional PM0.1 in all 39 cities. In addition, natural gas combustion made large contributions to PM0.1 concentrations due to the widespread use of this fuel for electricity generation, industrial applications, residential, and commercial use. However, the source composition of primary PM0.1 across many cities was notably different. Future epidemiological studies may be able to differentiate PM0.1 and PM2.5 health effects by contrasting cities with different ratios of PM0.1 / PM2.5.

ISBN: 9780438930766Subjects--Topical Terms:

2102064
Aeronomy.

Advances in Air Pollution Simulations for the United States: Ozone and Ultrafine Airborne Particulate Matter.
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520 $a Air pollution throughout the United States has changed dramatically over the past 50 years in response to numerous initiatives to protect public health. The improved efficiency of motor vehicles and adoption of stricter emission policies on coal-fired power plants are two of the reasons concentrations of criteria air pollutants have decreased. Despite nationwide reductions in most pollutant emissions, many urban regions throughout the United States still exceed unhealthy levels of criteria air pollutants. The underlying causes of these exceedances are difficult to determine as they may be the result of unidentified sources, certain meteorological conditions or changes to ambient pollutant concentrations that may alter the formation of secondary pollutants. In order to develop plans that manage these air pollution episodes, accurate tools that are used to resolve the underlying sources and chemical pathways are required. This dissertation describes three studies that improve our understanding of the causes of modern air pollution problems and provide insights that are useful for the development of the next generation air pollution abatement strategies. The first study explores the effectiveness of historical ozone control strategies by updating the calculation of the Maximum Incremental Reactivity (MIR) scale that predicts ozone production from volatile organic compounds (VOCs). Inputs to the MIR calculations were modernized from 1988 atmospheric conditions to 2010 conditions by accounting for changes in meteorology, emission rates, and background concentrations. The calculations show that the median MIR values across thirty nine cities in the United States decreased by approximately 20% due to the impact of emissions control programs on the atmospheric composition and updates in meteorological variables including temperature, humidity, and boundary layer height. Although the absolute MIR values decreased, the sorted MIR rank of each specific VOC did not change strongly compared to the original rankings calculated using 1988 conditions. These findings indicate that past decisions about ozone control strategies remain valid today and the MIR scale continues to provide relevant guidance for policy makers. The second study evaluates an updated version of the SAPRC chemical mechanism for the prediction of ambient ozone and peroxy-radical concentrations. The SAPRC16 mechanism represents more compounds explicitly and includes a new lumping scheme to improve toxics and SOA precursors compared to the previous SAPRC07 and SAPRC11 mechanisms. SAPRC16 was applied under ambient conditions in cities spanning the United States in order to determine if the improved performance observed during the simulation of smog chamber experiments translated to the real atmosphere. Concentrations of ozone, hydroxyl radical (OH) and hydroperoxyl (HO2) radical were predicted with SAPRC16 and SAPRC11, and compared to measured values. It was generally observed that SAPRC16 predicts slightly lower ozone concentrations than SAPRC11 in NOx rich urban centers. Predictions from SAPRC11 are in better agreement with the measurements in the western United States; however, SAPRC16 outperforms SAPRC11 in some eastern and southern U.S. cities. Ozone concentrations predicted by SAPRC16 and SAPRC11 diverged more as emissions decreased suggesting that the two mechanisms will predict different outcomes from increasingly stringent future emissions control programs. A box model analysis showed that the SAPRC16 mechanism quenches ozone production earlier than SAPRC11 as NOx concentrations increase (yielding decreased VOC/NOx ratios). This could be caused by more detailed HO2+RO2 reactions and RO2 isomerization reactions in SAPRC16 that compete with the HO2+NO reaction. The predictions of OH and HO2 were also evaluated for the two mechanisms using measurements from the CalNex field study in Pasadena. SARPC11 and SAPRC 16 prediction of OH are similar and within EPA criteria for mean fractional error (<0.75). However, SAPRC16 largely under predicts HO2 leading to the conclusion that further analysis of the HO2+RO2 reactions and RO2 isomerization reactions is needed before the SAPRC16 chemical mechanism is widely adopted. The final study described in this dissertation investigates the predicted concentration of PM0.1 in thirty-nine urban regions throughout the U.S. during summer pollution events in 2010. PM0.1 is a subset of PM2.5 that has been measured to have high toxicity and has been found to be associated with Ischemic Heart Disease (IHD) mortality in recent epidemiological studies. Artificial source tags were used to track contributions to primary PM0.1 and PM2.5 from fifteen source categories. On-road gasoline vehicles, diesel vehicles, and food cooking significantly contributed to regional PM0.1 in all 39 cities. In addition, natural gas combustion made large contributions to PM0.1 concentrations due to the widespread use of this fuel for electricity generation, industrial applications, residential, and commercial use. However, the source composition of primary PM0.1 across many cities was notably different. Future epidemiological studies may be able to differentiate PM0.1 and PM2.5 health effects by contrasting cities with different ratios of PM0.1 / PM2.5.
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