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• 1. [Article] FAGE measurements of tropospheric HO with measurements and model of interferences

  Ambient HO measurements by low-pressure laser-excited fluorescence with chemical modulation, and supporting ozone and water-vapor data, are presented for periods in May and August 1987. The observed peak ...

  Citation × Citation Citation Abstract Copy Title: FAGE measurements of tropospheric HO with measurements and model of interferences Author: Hard, Thomas M., Mehrabzadeh, A. A., Chan, C. Y., O'Brien, Robert J. Year: 1992 Ambient HO measurements by low-pressure laser-excited fluorescence with chemical modulation, and supporting ozone and water-vapor data, are presented for periods in May and August 1987. The observed peak daytime ambient HO concentrations in Oregon are in the range (2.5 to 8) times106 molecules cm⁻³ and show small negative offsets due to photochemical interference. Direct measurements of the interference at fixed [O₃] give the dependence on ambient [H₂O] and on the modulating reagent [isobutane]. At ambient [O₃]=30 p.p.b. and 10 torr H₂O, with excitation and detection at a total pressure of 4 torr, the net interference is equal to [HO]=-1.3times10⁶ molecule cm⁻³. Title: FAGE measurements of tropospheric HO with measurements and model of interferences Author: Hard, Thomas M., Mehrabzadeh, A. A., Chan, C. Y., O'Brien, Robert J. Year: 1992 Ambient HO measurements by low-pressure laser-excited fluorescence with chemical modulation, and supporting ozone and water-vapor data, are presented for periods in May and August 1987. The observed peak daytime ambient HO concentrations in Oregon are in the range (2.5 to 8) times106 molecules cm⁻³ and show small negative offsets due to photochemical interference. Direct measurements of the interference at fixed [O₃] give the dependence on ambient [H₂O] and on the modulating reagent [isobutane]. At ambient [O₃]=30 p.p.b. and 10 torr H₂O, with excitation and detection at a total pressure of 4 torr, the net interference is equal to [HO]=-1.3times10⁶ molecule cm⁻³. Close

• 2. [Article] Diurnal HO₂ cycles at clean air and urban sites in the troposphere

  HO₂ concentrations have been determined at two Oregon sites for continuous periods of 36 to 48 hours, using fluorescence assay with gas expansion. At the sea level coastal site (45degN 124degW), NNW winds ...

  Citation × Citation Citation Abstract Copy Title: Diurnal HO₂ cycles at clean air and urban sites in the troposphere Author: Hard, Thomas M., Chan, C. Y., Mehrabzadeh, A. A., O'Brien, Robert J. Year: 1992 HO₂ concentrations have been determined at two Oregon sites for continuous periods of 36 to 48 hours, using fluorescence assay with gas expansion. At the sea level coastal site (45degN 124degW), NNW winds prevailed during daytime, and a point measurement of very low total nonmethane hydrocarbon concentration indicated the presence of remote tropospheric air of oceanic origin. At the urban site, HO₂ was determined during moderately low ozone pollution levels. At both sites, maximum daily [HO₂] was in the range of 1-2times10⁸ cm⁻³ under clear-sky conditions, with an estimated overall uncertainty of 40%. Title: Diurnal HO₂ cycles at clean air and urban sites in the troposphere Author: Hard, Thomas M., Chan, C. Y., Mehrabzadeh, A. A., O'Brien, Robert J. Year: 1992 HO₂ concentrations have been determined at two Oregon sites for continuous periods of 36 to 48 hours, using fluorescence assay with gas expansion. At the sea level coastal site (45degN 124degW), NNW winds prevailed during daytime, and a point measurement of very low total nonmethane hydrocarbon concentration indicated the presence of remote tropospheric air of oceanic origin. At the urban site, HO₂ was determined during moderately low ozone pollution levels. At both sites, maximum daily [HO₂] was in the range of 1-2times10⁸ cm⁻³ under clear-sky conditions, with an estimated overall uncertainty of 40%. Close

• 3. [Article] Designing More Effective Air Quality Advisories

  Background: There is increasing concern about the impact of air quality on human health in urban environments and how to best reduce impacts through public policies. An NSF Biocomplexity Project - "Feedbacks ...

  Citation × Citation Citation Abstract Copy Title: Designing More Effective Air Quality Advisories Author: Olexy, Justin Year: 2008 Background: There is increasing concern about the impact of air quality on human health in urban environments and how to best reduce impacts through public policies. An NSF Biocomplexity Project - "Feedbacks between Urban Systems and the Environment" (FUSE), led by Portland State University, studies the human feedbacks and responses to air quality and heat advisories through data collected in city-wide phone surveys in Portland, OR and Houston, TX. On days when ozone levels are predicted to exceed air quality standards, regulatory agencies issue air quality advisories which ask residents to reduce certain air polluting behaviors such as driving and lawn mowing. However, there have been very few studies of the effectiveness of these systems. Previous work documented that in both Portland and Houston, around ~10% of the population respond to voluntary advisories (Semenza et. al, 2008). In the testbed cities, the survey also asked respondents questions about their personal emissions-related behavior such as driving, mowing, use of household products, etc., as well as how that behavior was effected by an air quality advisory. Objectives: In this project, the survey data is used to accomplish three major tasks. Firstly, to estimate emissions based on the survey responses. For example, estimating VOC emissions based on reported mowing behavior (size of lawn, frequency of mowing, and type of mower). Secondly, to compare reported behavior during normal days to behavior during air advisory days. And finally, to compare the emissions estimates to demographic data (such as population density) to find any trends. For example, can variations in emission patterns be predicted using a demographic characteristic such as housing density? Currently the EPA and the Oregon DEQ estimate many types of emissions on a per capita basis. These per capita emissions numbers are generally not adjusted for any local demographic information. One additional use of this research could be to improve current emissions estimation methods. Methods: Survey responses to questions about emissions related behavior were used as activity factors in emissions calculations. The emission estimations were then tested against demographics such as housing density. For the purpose of graphical representation, housing density was broken into four quartiles to represent four different levels of density. For statistical analysis housing density was not categorized. Results: Emissions behavior, in several cases, appears to be linked to demographic features such as housing density. Per capita lawn care hydrocarbon emissions, vehicle emissions, and several consumer product category emissions trend higher towards lower housing density in both Portland and Houston. Conclusions: The results of this research project could be used to tailor air quality advisories to better target their audience with appropriate messages, thereby more effectively improving air quality during potentially hazardous air quality conditions. Understanding demographic elements to emissions estimation could be used by environmental agencies to produce better emission estimations. Title: Designing More Effective Air Quality Advisories Author: Olexy, Justin Year: 2008 Background: There is increasing concern about the impact of air quality on human health in urban environments and how to best reduce impacts through public policies. An NSF Biocomplexity Project - "Feedbacks between Urban Systems and the Environment" (FUSE), led by Portland State University, studies the human feedbacks and responses to air quality and heat advisories through data collected in city-wide phone surveys in Portland, OR and Houston, TX. On days when ozone levels are predicted to exceed air quality standards, regulatory agencies issue air quality advisories which ask residents to reduce certain air polluting behaviors such as driving and lawn mowing. However, there have been very few studies of the effectiveness of these systems. Previous work documented that in both Portland and Houston, around ~10% of the population respond to voluntary advisories (Semenza et. al, 2008). In the testbed cities, the survey also asked respondents questions about their personal emissions-related behavior such as driving, mowing, use of household products, etc., as well as how that behavior was effected by an air quality advisory. Objectives: In this project, the survey data is used to accomplish three major tasks. Firstly, to estimate emissions based on the survey responses. For example, estimating VOC emissions based on reported mowing behavior (size of lawn, frequency of mowing, and type of mower). Secondly, to compare reported behavior during normal days to behavior during air advisory days. And finally, to compare the emissions estimates to demographic data (such as population density) to find any trends. For example, can variations in emission patterns be predicted using a demographic characteristic such as housing density? Currently the EPA and the Oregon DEQ estimate many types of emissions on a per capita basis. These per capita emissions numbers are generally not adjusted for any local demographic information. One additional use of this research could be to improve current emissions estimation methods. Methods: Survey responses to questions about emissions related behavior were used as activity factors in emissions calculations. The emission estimations were then tested against demographics such as housing density. For the purpose of graphical representation, housing density was broken into four quartiles to represent four different levels of density. For statistical analysis housing density was not categorized. Results: Emissions behavior, in several cases, appears to be linked to demographic features such as housing density. Per capita lawn care hydrocarbon emissions, vehicle emissions, and several consumer product category emissions trend higher towards lower housing density in both Portland and Houston. Conclusions: The results of this research project could be used to tailor air quality advisories to better target their audience with appropriate messages, thereby more effectively improving air quality during potentially hazardous air quality conditions. Understanding demographic elements to emissions estimation could be used by environmental agencies to produce better emission estimations. Close