Jennifer Richmond-bryant - Academia.edu (original) (raw)
Papers by Jennifer Richmond-bryant
Environmental Science & Technology
The objective of this work is to examine associations between blood Pb (PbB) and air Pb (PbA) in ... more The objective of this work is to examine associations between blood Pb (PbB) and air Pb (PbA) in particulate matter measured at different size increments using PbB concentrations from the National Health and Nutrition Examination Survey and PbA concentrations from the U.S. EPA for 1999-2008. Three size fractions of particle-bound PbA (TSP, PM10 and PM2.5) data with different averaging times (current and past 90-d average) were utilized. A multi-level linear mixed effect model was used to characterize the PbB-PbA relationship. At 0.15 µg/m3, a unit decrease in PbA in PM10 was significantly associated with a decrease in PbB of 0.3-2.2 µg/dL across age groups and averaging times. For PbA in PM2.5 and TSP, slopes were generally positive but not significant. PbB levels were more sensitive to the change in PbA concentrations for children (1-5 y, 6-11 y) and older adults (≥ 60 y) than teenagers (12-19 y) and adults (20-59 y). For the years following the phase-out of Pb in gasoline and a re...
Population health metrics, 2015
Metabolic syndrome (MetS) is the co-occurrence of several conditions that increase risk of chroni... more Metabolic syndrome (MetS) is the co-occurrence of several conditions that increase risk of chronic disease and mortality. Multivariate models for calculating risk of MetS-related diseases based on combinations of biomarkers are promising for future risk estimation if based on large population samples. Given biomarkers' nonspecificity and commonality in predicting diseases, we hypothesized that unique combinations of the same clinical diagnostic criteria can be used in different multivariate models to develop more accurate individual and cumulative risk estimates for specific MetS-related diseases. We utilized adult biomarker and cardiovascular disease (CVD) data from the National Health and Nutrition Examination Survey as part of a cross-sectional analysis. Serum C-reactive protein (CRP), glycohemoglobin, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, total cholesterol, fasting glucose, and apolipoprotein-B were modeled. CVDs included c...
Toxicology, 2015
The peer-reviewed literature on the health and ecological effects of lead (Pb) indicates common e... more The peer-reviewed literature on the health and ecological effects of lead (Pb) indicates common effects and underlying modes of action across multiple organisms for several endpoints. Based on such observations, the United States (U.S.) Environmental Protection Agency (EPA) applied a cross-species approach in the 2013 Integrated Science Assessment (ISA) for Lead for evaluating the causality of relationships between Pb exposure and specific endpoints that are shared by humans, laboratory animals, and ecological receptors (i.e., hematological effects, reproductive and developmental effects, and nervous system effects). Other effects of Pb (i.e., cardiovascular, renal, and inflammatory responses) are less commonly assessed in aquatic and terrestrial wildlife limiting the application of cross-species comparisons. Determinations of causality in ISAs are guided by a framework for classifying the weight of evidence across scientific disciplines and across related effects by considering aspects such as biological plausibility and coherence. As illustrated for effects of Pb where evidence across species exists, the integration of coherent effects and common underlying modes of action can serve as a means to substantiate conclusions regarding the causal nature of the health and ecological effects of environmental toxicants.
Journal of Exposure Science and Environmental Epidemiology, 2014
There is abundant literature finding that susceptibility factors, including race and ethnicity, a... more There is abundant literature finding that susceptibility factors, including race and ethnicity, age, and housing, directly influence blood lead levels. No study has explored how susceptibility factors influence the blood lead-air lead relationship nationally. The objective is to evaluate whether susceptibility factors act as effect measure modifiers on the blood lead-air lead relationship. Participant level blood lead data from the 1999 to 2008 National Health and Nutrition Examination Survey were merged with air lead data from the US Environmental Protection Agency. Linear mixed effects models were run with and without an air lead interaction term for age group, sex, housing age, or race/ethnicity to determine whether these factors are effect measure modifiers for all ages combined and for five age brackets. Age group and race/ethnicity were determined to be effect measure modifiers in the all-age model and for some age groups. Being a child (1-5, 6-11, and 12-19 years) or of Mexican-American ethnicity increased the effect estimate. Living in older housing (built before 1950) decreased the effect estimate for all models except for the 1-5-year group, where older housing was an effect measure modifier. These results are consistent with the peer-reviewed literature of time-activity patterns, ventilation, and toxicokinetics.Journal of Exposure Science and Environmental Epidemiology advance online publication, 25 June 2014; doi:10.1038/jes.2014.46.
Science of The Total Environment, 2014
Science of The Total Environment, 2013
Journal of Environmental Monitoring, 2009
National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Thi... more National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. This work constitutes a contribution to the NOAA Air Quality Program.
Journal of Environmental Monitoring, 2009
Journal of Environmental Monitoring, 2009
matter (PM) across urban intersections. Experiments were performed in a street canyon perpendicul... more matter (PM) across urban intersections. Experiments were performed in a street canyon perpendicular to a highway in Brooklyn, NY, USA. Real-time ultrafine PM samplers were positioned on either side of an intersection at multiple locations along a street to collect time-series number concentration data. Meteorology equipment was positioned within the street canyon and at an upstream background site to measure wind speed and direction. Time-series analysis was performed on the PM data to compute a transport velocity along the direction of the street for the cases where background winds were parallel and perpendicular to the street. The data were analyzed for sampler pairs located (1) on opposite sides of the intersection and (2) on the same block. The time-series analysis demonstrated along-street transport, including across the intersection when background winds were parallel to the street canyon and there was minimal transport and no communication across the intersection when background winds were perpendicular to the street canyon. Low but significant values of the cross-correlation function (CCF) underscore the turbulent nature of plume transport along the street canyon. The low correlations suggest that flow switching around corners or traffic-induced turbulence at the intersection may have aided dilution of the PM plume from the highway. This observation supports similar findings in the literature. Furthermore, the time-series analysis methodology applied in this study is introduced as a technique for studying spatiotemporal variation in the urban microscale environment.
Journal of Environmental Monitoring, 2009
The Brooklyn Traffic Real-Time Ambient Pollutant Penetration and Environmental Dispersion (B-TRAP... more The Brooklyn Traffic Real-Time Ambient Pollutant Penetration and Environmental Dispersion (B-TRAPPED) study, conducted in Brooklyn, NY, USA, in 2005, was designed with multiple goals in mind, two of which were contaminant source characterization and street canyon transport and dispersion monitoring. In the portion of the study described here, synchronized wind velocity and azimuth as well as particulate matter (PM) concentrations at multiple locations along 33rd Street were used to determine the feasibility of using traffic emissions in a complex urban topography as a sole tracer for studying urban contaminant transport. We demonstrate in this paper that it is possible to link downwind concentrations of contaminants in an urban street canyon to the vehicular traffic cycle using Eigen-frequency analysis. In addition, multivariable circular histograms are used to establish directional frequency maxima for wind velocity and contaminant concentration.
Journal of Environmental Monitoring, 2009
High-density housing in close proximity to freeways in conjunction with high concentrations of tr... more High-density housing in close proximity to freeways in conjunction with high concentrations of traffic emissions may contribute to significant degradation of indoor air quality. Densely populated areas may also be targeted for intentional releases of biological or chemical agents because an urban release could result in higher morbidity and mortality from the attack. Since people tend to spend the majority of their time indoors, it is paramount to explore the relationships between outdoor and indoor air quality and, specifically, the time scales that characterize transport of airborne contaminants from outdoors to indoors. In the Brooklyn Traffic Real-Time Ambient Pollutant Penetration and Environmental Dispersion (B-TRAPPED) study, a three-story row house with a flat face and roof and multiple rooms was used to investigate outdoor-to-indoor contaminant time scales. The building was located in the Sunset Park neighborhood of Brooklyn, NY, USA, in the vicinity of a major expressway and a heavily trafficked arterial road. It was found that the building shell has a profound impact on the indoor concentrations. A strong hourly periodicity (see Eisner et al., this issue, DOI: 10.1039/b907132f) in concentration outside the building during the morning "rush hour" was used as evidence to suggest that indoor contaminants originated from outdoor air penetration. Although the indoor concentrations followed a similar pattern, indoor concentrations were found to be more persistent than outdoor concentrations. Stronger persistency is used here to describe the tendency of the indoor concentration to continue to rise even if the outdoor concentration has started to drop, or vice versa. This may be an important factor in assessing negative health risks to inhabitants or first responders. A cross-correlation technique was employed to study the correlation between outdoor and indoor time series. In the high-density housing residential building used in the study, it was found that a long lag time exists (11 min) before indoor and outdoor concentrations reach maximal correlation.
Journal of Environmental Monitoring, 2009
The Brooklyn traffic real-time ambient pollutant penetration and environmental dispersion (B-TRAP... more The Brooklyn traffic real-time ambient pollutant penetration and environmental dispersion (B-TRAPPED) study was a multidisciplinary field research project that investigated the transport, dispersion, and infiltration processes of traffic emission particulate matter (PM) pollutants in a near-highway urban residential area. The urban PM transport, dispersion, and infiltration processes were described mathematically in a theoretical model that was constructed to develop the experimental objectives of the B-TRAPPED study. In the study, simultaneous and continuous time-series PM concentration and meteorological data collected at multiple outdoor and indoor monitoring locations were used to characterize both temporal and spatial patterns of the PM concentration movements within microscale distances (<500 m) from the highway. Objectives of the study included (1) characterizing the temporal and spatial PM concentration fluctuation and distribution patterns in the urban street canyon; (2) investigating the effects of urban structures such as a tall building or an intersection on the transport and dispersion of PM; (3) studying the influence of meteorological variables on the transport, dispersion, and infiltration processes; (4) characterizing the relationships between the building parameters and the infiltration mechanisms; (5) establishing a cause-and-effect relationship between outdoor-released PM and indoor PM concentrations and identifying the dominant mechanisms involved in the infiltration process; (6) evaluating the effectiveness of a shelter-in-place area for protection against outdoor-released PM pollutants; and (7) understanding the predominant airflow and pollutant dispersion patterns within the neighborhood using wind tunnel and CFD simulations. The 10 papers in this first set of papers presenting the results from the B-TRAPPED study address these objectives. This paper describes the theoretical background and models representing the interrelated processes of transport, dispersion, and infiltration. The theoretical solution for the relationship between the time-dependent indoor PM concentration and the initial PM concentration at the outdoor source was obtained. The theoretical models and solutions helped us to identify important parameters in the processes of transport, dispersion, and infiltration. The B-TRAPPED study field experiments were then designed to investigate these parameters in the hope of better understanding urban PM pollutant behaviors.
Indoor Air, 2006
The objective of this study is to test a technique used to analyze contaminant transport in the w... more The objective of this study is to test a technique used to analyze contaminant transport in the wake of a bluff body under controlled experimental conditions for application to aerosol transport in a complex furnished room. Specifically, the hypothesis tested by our work is that the dispersion of contaminants in a room is related to the turbulence kinetic energy and length scale. This turbulence is, in turn, determined by the size and shape of furnishings within the room and by the ventilation characteristics. This approach was tested for indoor dispersion through computational fluid dynamics simulations and laboratory experiments. In each, 3 mum aerosols were released in a furnished room with varied contaminant release locations (at the inlet vent or under a desk). The realizable k approximately epsilon model was employed in the simulations, followed by a Lagrangian particle trajectory simulation used as input for an in-house FORTRAN code to compute aerosol concentration. For the experiments, concentrations were measured simultaneously at seven locations by laser photometry, and air velocity was measured using laser Doppler velocimetry. The results suggest that turbulent diffusion is a significant factor in contaminant residence time in a furnished room. This procedure was then expanded to develop a simplified correlation between contaminant residence time and the number of enclosing surfaces around a point containing the contaminant. Practical Implications The work presented here provides a methodology for relating local aerosol residence time to properties of room ventilation and furniture arrangement. This technique may be used to assess probable locations of high concentration by knowing only the particle release location, furniture configuration, inlet and outlet locations, and air speeds, which are all observable features. Applications of this method include development of 'rules of thumb' for first responders entering a room where an agent has been released and selection of sampler locations to monitor conditions in sensitive areas.
Global and Planetary Change, 2013
Aim This paper describes the characteristics of the spatio-temporal distribution of vegetation fi... more Aim This paper describes the characteristics of the spatio-temporal distribution of vegetation fires as detected from satellite data for the 12 months April 1992 to March 1993.
Environmental Health Perspectives, 2014
Background: It is difficult to discern the proportion of blood lead (PbB) attributable to ambient... more Background: It is difficult to discern the proportion of blood lead (PbB) attributable to ambient air lead (PbA), given the multitude of lead (Pb) sources and pathways of exposure. The PbB-PbA relationship has previously been evaluated across populations. This relationship was a central consideration in the 2008 review of the Pb national ambient air quality standards. oBjectives: The objectives of this study were to evaluate the relationship between PbB and PbA concentrations among children nationwide for recent years and to compare the relationship with those obtained from other studies in the literature. Methods: We merged participant-level data for PbB from the National Health and Nutrition Examination Survey (NHANES) III (1988-1994) and NHANES 9908 (1999-2008) with PbA data from the U.S. Environmental Protection Agency. We applied mixed-effects models, and we computed slope factor, d[PbB]/d[PbA] or the change in PbB per unit change in PbA, from the model results to assess the relationship between PbB and PbA. results: Comparing the NHANES regression results with those from the literature shows that slope factor increased with decreasing PbA among children 0-11 years of age. conclusion: These findings suggest that a larger relative public health benefit may be derived among children from decreases in PbA at low PbA exposures. Simultaneous declines in Pb from other sources, changes in PbA sampling uncertainties over time largely related to changes in the size distribution of Pb-bearing particulate matter, and limitations regarding sampling size and exposure error may contribute to the variability in slope factor observed across peer-reviewed studies. citation: Richmond-Bryant J, Meng Q, Davis A, Cohen J, Lu SE, Svendsgaard D, Brown JS, Tuttle L, Hubbard H, Rice J, Kirrane E, Vinikoor-Imler LC, Kotchmar D, Hines EP, Ross M. 2014. The Influence of declining air lead levels on blood lead-air lead slope factors in children. Environ Health Perspect 122:754-760; http://dx.
Building and Environment, 2006
Monitoring of aerosols is typically performed over 3 h to diurnal time scales for outdoor concent... more Monitoring of aerosols is typically performed over 3 h to diurnal time scales for outdoor concentration levels and 15 min to 8 h scales indoors. At these scales, concentration is assumed to be well mixed with little spatio-temporal variability around the sampler. Less attention has been given to the potential for acute exposure to contaminants during the initial minutes after a point-source release, where point-wise concentrations may greatly exceed the well-mixed conditions. Here, we seek to demonstrate that the commonly used well-mixed assumption is flawed in the first minutes after a contaminant is released because point-wise concentration levels are initially highly non-uniform and are influenced by turbulent structures caused by the presence of obstacles in the room. This assumption was examined by releasing 3 mm aerosols in a test room with HEPA filter ventilation and by varying controlled conditions of room furnishings (furnished vs. unfurnished) and contaminant release locations (at the inlet vent or under a desk). For each experiment, aerosol concentrations were measured simultaneously at seven locations by nephelometry. Complementary computational fluid dynamics simulations were performed to lend confidence to the experiments and to provide detailed pictures of the velocity and particle concentration profiles. The experimental and numerical results corroborated the hypothesis. For both release locations in the furnished room, a completely well-mixed condition did not occur 600 s after the release, and aerosol dispersion was dictated by the turbulent airflow pattern. For the empty room, there was significantly less spatial variability in the point-wise measured concentrations after 300 s than for the furnished room. This information may aid in evaluating the potential for occupant exposure to aerosolized hazardous substances and in supporting optimization of detector placement. Published by Elsevier Ltd.
Environmental Health Perspectives, 2013
Background: This paper presents an application of quantitative ion character-activity relationshi... more Background: This paper presents an application of quantitative ion character-activity relationships (QICAR) to estimate associations of human cardiovascular (CV) diseases (CVDs) with a set of metal ion properties commonly observed in ambient air pollutants. QICAR has previously been used to predict ecotoxicity of inorganic metal ions based on ion properties. oBjectives: The objective of this work was to examine potential associations of biological end points with a set of physical and chemical properties describing inorganic metal ions present in exposures using QICAR. Methods: Chemical and physical properties of 17 metal ions were obtained from peer-reviewed publications. Associations of cardiac arrhythmia, myocardial ischemia, myocardial infarction, stroke, and thrombosis with exposures to metal ions (measured as inference scores) were obtained from the Comparative Toxicogenomics Database (CTD). Robust regressions were applied to estimate the associations of CVDs with ion properties. results: CVD was statistically significantly associated (Bonferroni-adjusted significance level of 0.003) with many ion properties reflecting ion size, solubility, oxidation potential, and abilities to form covalent and ionic bonds. The properties are relevant for reactive oxygen species (ROS) generation, which has been identified as a possible mechanism leading to CVDs. conclusion: QICAR has the potential to complement existing epidemiologic methods for estimating associations between CVDs and air pollutant exposures by providing clues about the underlying mechanisms that may explain these associations. key words: air pollution, cardiovascular disease, multipollutant, QICAR, QSAR. Environ Health Perspect 121:558-564 (2013). http://dx.
Environmental Science & Technology
The objective of this work is to examine associations between blood Pb (PbB) and air Pb (PbA) in ... more The objective of this work is to examine associations between blood Pb (PbB) and air Pb (PbA) in particulate matter measured at different size increments using PbB concentrations from the National Health and Nutrition Examination Survey and PbA concentrations from the U.S. EPA for 1999-2008. Three size fractions of particle-bound PbA (TSP, PM10 and PM2.5) data with different averaging times (current and past 90-d average) were utilized. A multi-level linear mixed effect model was used to characterize the PbB-PbA relationship. At 0.15 µg/m3, a unit decrease in PbA in PM10 was significantly associated with a decrease in PbB of 0.3-2.2 µg/dL across age groups and averaging times. For PbA in PM2.5 and TSP, slopes were generally positive but not significant. PbB levels were more sensitive to the change in PbA concentrations for children (1-5 y, 6-11 y) and older adults (≥ 60 y) than teenagers (12-19 y) and adults (20-59 y). For the years following the phase-out of Pb in gasoline and a re...
Population health metrics, 2015
Metabolic syndrome (MetS) is the co-occurrence of several conditions that increase risk of chroni... more Metabolic syndrome (MetS) is the co-occurrence of several conditions that increase risk of chronic disease and mortality. Multivariate models for calculating risk of MetS-related diseases based on combinations of biomarkers are promising for future risk estimation if based on large population samples. Given biomarkers' nonspecificity and commonality in predicting diseases, we hypothesized that unique combinations of the same clinical diagnostic criteria can be used in different multivariate models to develop more accurate individual and cumulative risk estimates for specific MetS-related diseases. We utilized adult biomarker and cardiovascular disease (CVD) data from the National Health and Nutrition Examination Survey as part of a cross-sectional analysis. Serum C-reactive protein (CRP), glycohemoglobin, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, total cholesterol, fasting glucose, and apolipoprotein-B were modeled. CVDs included c...
Toxicology, 2015
The peer-reviewed literature on the health and ecological effects of lead (Pb) indicates common e... more The peer-reviewed literature on the health and ecological effects of lead (Pb) indicates common effects and underlying modes of action across multiple organisms for several endpoints. Based on such observations, the United States (U.S.) Environmental Protection Agency (EPA) applied a cross-species approach in the 2013 Integrated Science Assessment (ISA) for Lead for evaluating the causality of relationships between Pb exposure and specific endpoints that are shared by humans, laboratory animals, and ecological receptors (i.e., hematological effects, reproductive and developmental effects, and nervous system effects). Other effects of Pb (i.e., cardiovascular, renal, and inflammatory responses) are less commonly assessed in aquatic and terrestrial wildlife limiting the application of cross-species comparisons. Determinations of causality in ISAs are guided by a framework for classifying the weight of evidence across scientific disciplines and across related effects by considering aspects such as biological plausibility and coherence. As illustrated for effects of Pb where evidence across species exists, the integration of coherent effects and common underlying modes of action can serve as a means to substantiate conclusions regarding the causal nature of the health and ecological effects of environmental toxicants.
Journal of Exposure Science and Environmental Epidemiology, 2014
There is abundant literature finding that susceptibility factors, including race and ethnicity, a... more There is abundant literature finding that susceptibility factors, including race and ethnicity, age, and housing, directly influence blood lead levels. No study has explored how susceptibility factors influence the blood lead-air lead relationship nationally. The objective is to evaluate whether susceptibility factors act as effect measure modifiers on the blood lead-air lead relationship. Participant level blood lead data from the 1999 to 2008 National Health and Nutrition Examination Survey were merged with air lead data from the US Environmental Protection Agency. Linear mixed effects models were run with and without an air lead interaction term for age group, sex, housing age, or race/ethnicity to determine whether these factors are effect measure modifiers for all ages combined and for five age brackets. Age group and race/ethnicity were determined to be effect measure modifiers in the all-age model and for some age groups. Being a child (1-5, 6-11, and 12-19 years) or of Mexican-American ethnicity increased the effect estimate. Living in older housing (built before 1950) decreased the effect estimate for all models except for the 1-5-year group, where older housing was an effect measure modifier. These results are consistent with the peer-reviewed literature of time-activity patterns, ventilation, and toxicokinetics.Journal of Exposure Science and Environmental Epidemiology advance online publication, 25 June 2014; doi:10.1038/jes.2014.46.
Science of The Total Environment, 2014
Science of The Total Environment, 2013
Journal of Environmental Monitoring, 2009
National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Thi... more National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. This work constitutes a contribution to the NOAA Air Quality Program.
Journal of Environmental Monitoring, 2009
Journal of Environmental Monitoring, 2009
matter (PM) across urban intersections. Experiments were performed in a street canyon perpendicul... more matter (PM) across urban intersections. Experiments were performed in a street canyon perpendicular to a highway in Brooklyn, NY, USA. Real-time ultrafine PM samplers were positioned on either side of an intersection at multiple locations along a street to collect time-series number concentration data. Meteorology equipment was positioned within the street canyon and at an upstream background site to measure wind speed and direction. Time-series analysis was performed on the PM data to compute a transport velocity along the direction of the street for the cases where background winds were parallel and perpendicular to the street. The data were analyzed for sampler pairs located (1) on opposite sides of the intersection and (2) on the same block. The time-series analysis demonstrated along-street transport, including across the intersection when background winds were parallel to the street canyon and there was minimal transport and no communication across the intersection when background winds were perpendicular to the street canyon. Low but significant values of the cross-correlation function (CCF) underscore the turbulent nature of plume transport along the street canyon. The low correlations suggest that flow switching around corners or traffic-induced turbulence at the intersection may have aided dilution of the PM plume from the highway. This observation supports similar findings in the literature. Furthermore, the time-series analysis methodology applied in this study is introduced as a technique for studying spatiotemporal variation in the urban microscale environment.
Journal of Environmental Monitoring, 2009
The Brooklyn Traffic Real-Time Ambient Pollutant Penetration and Environmental Dispersion (B-TRAP... more The Brooklyn Traffic Real-Time Ambient Pollutant Penetration and Environmental Dispersion (B-TRAPPED) study, conducted in Brooklyn, NY, USA, in 2005, was designed with multiple goals in mind, two of which were contaminant source characterization and street canyon transport and dispersion monitoring. In the portion of the study described here, synchronized wind velocity and azimuth as well as particulate matter (PM) concentrations at multiple locations along 33rd Street were used to determine the feasibility of using traffic emissions in a complex urban topography as a sole tracer for studying urban contaminant transport. We demonstrate in this paper that it is possible to link downwind concentrations of contaminants in an urban street canyon to the vehicular traffic cycle using Eigen-frequency analysis. In addition, multivariable circular histograms are used to establish directional frequency maxima for wind velocity and contaminant concentration.
Journal of Environmental Monitoring, 2009
High-density housing in close proximity to freeways in conjunction with high concentrations of tr... more High-density housing in close proximity to freeways in conjunction with high concentrations of traffic emissions may contribute to significant degradation of indoor air quality. Densely populated areas may also be targeted for intentional releases of biological or chemical agents because an urban release could result in higher morbidity and mortality from the attack. Since people tend to spend the majority of their time indoors, it is paramount to explore the relationships between outdoor and indoor air quality and, specifically, the time scales that characterize transport of airborne contaminants from outdoors to indoors. In the Brooklyn Traffic Real-Time Ambient Pollutant Penetration and Environmental Dispersion (B-TRAPPED) study, a three-story row house with a flat face and roof and multiple rooms was used to investigate outdoor-to-indoor contaminant time scales. The building was located in the Sunset Park neighborhood of Brooklyn, NY, USA, in the vicinity of a major expressway and a heavily trafficked arterial road. It was found that the building shell has a profound impact on the indoor concentrations. A strong hourly periodicity (see Eisner et al., this issue, DOI: 10.1039/b907132f) in concentration outside the building during the morning &amp;amp;amp;amp;amp;amp;amp;quot;rush hour&amp;amp;amp;amp;amp;amp;amp;quot; was used as evidence to suggest that indoor contaminants originated from outdoor air penetration. Although the indoor concentrations followed a similar pattern, indoor concentrations were found to be more persistent than outdoor concentrations. Stronger persistency is used here to describe the tendency of the indoor concentration to continue to rise even if the outdoor concentration has started to drop, or vice versa. This may be an important factor in assessing negative health risks to inhabitants or first responders. A cross-correlation technique was employed to study the correlation between outdoor and indoor time series. In the high-density housing residential building used in the study, it was found that a long lag time exists (11 min) before indoor and outdoor concentrations reach maximal correlation.
Journal of Environmental Monitoring, 2009
The Brooklyn traffic real-time ambient pollutant penetration and environmental dispersion (B-TRAP... more The Brooklyn traffic real-time ambient pollutant penetration and environmental dispersion (B-TRAPPED) study was a multidisciplinary field research project that investigated the transport, dispersion, and infiltration processes of traffic emission particulate matter (PM) pollutants in a near-highway urban residential area. The urban PM transport, dispersion, and infiltration processes were described mathematically in a theoretical model that was constructed to develop the experimental objectives of the B-TRAPPED study. In the study, simultaneous and continuous time-series PM concentration and meteorological data collected at multiple outdoor and indoor monitoring locations were used to characterize both temporal and spatial patterns of the PM concentration movements within microscale distances (<500 m) from the highway. Objectives of the study included (1) characterizing the temporal and spatial PM concentration fluctuation and distribution patterns in the urban street canyon; (2) investigating the effects of urban structures such as a tall building or an intersection on the transport and dispersion of PM; (3) studying the influence of meteorological variables on the transport, dispersion, and infiltration processes; (4) characterizing the relationships between the building parameters and the infiltration mechanisms; (5) establishing a cause-and-effect relationship between outdoor-released PM and indoor PM concentrations and identifying the dominant mechanisms involved in the infiltration process; (6) evaluating the effectiveness of a shelter-in-place area for protection against outdoor-released PM pollutants; and (7) understanding the predominant airflow and pollutant dispersion patterns within the neighborhood using wind tunnel and CFD simulations. The 10 papers in this first set of papers presenting the results from the B-TRAPPED study address these objectives. This paper describes the theoretical background and models representing the interrelated processes of transport, dispersion, and infiltration. The theoretical solution for the relationship between the time-dependent indoor PM concentration and the initial PM concentration at the outdoor source was obtained. The theoretical models and solutions helped us to identify important parameters in the processes of transport, dispersion, and infiltration. The B-TRAPPED study field experiments were then designed to investigate these parameters in the hope of better understanding urban PM pollutant behaviors.
Indoor Air, 2006
The objective of this study is to test a technique used to analyze contaminant transport in the w... more The objective of this study is to test a technique used to analyze contaminant transport in the wake of a bluff body under controlled experimental conditions for application to aerosol transport in a complex furnished room. Specifically, the hypothesis tested by our work is that the dispersion of contaminants in a room is related to the turbulence kinetic energy and length scale. This turbulence is, in turn, determined by the size and shape of furnishings within the room and by the ventilation characteristics. This approach was tested for indoor dispersion through computational fluid dynamics simulations and laboratory experiments. In each, 3 mum aerosols were released in a furnished room with varied contaminant release locations (at the inlet vent or under a desk). The realizable k approximately epsilon model was employed in the simulations, followed by a Lagrangian particle trajectory simulation used as input for an in-house FORTRAN code to compute aerosol concentration. For the experiments, concentrations were measured simultaneously at seven locations by laser photometry, and air velocity was measured using laser Doppler velocimetry. The results suggest that turbulent diffusion is a significant factor in contaminant residence time in a furnished room. This procedure was then expanded to develop a simplified correlation between contaminant residence time and the number of enclosing surfaces around a point containing the contaminant. Practical Implications The work presented here provides a methodology for relating local aerosol residence time to properties of room ventilation and furniture arrangement. This technique may be used to assess probable locations of high concentration by knowing only the particle release location, furniture configuration, inlet and outlet locations, and air speeds, which are all observable features. Applications of this method include development of 'rules of thumb' for first responders entering a room where an agent has been released and selection of sampler locations to monitor conditions in sensitive areas.
Global and Planetary Change, 2013
Aim This paper describes the characteristics of the spatio-temporal distribution of vegetation fi... more Aim This paper describes the characteristics of the spatio-temporal distribution of vegetation fires as detected from satellite data for the 12 months April 1992 to March 1993.
Environmental Health Perspectives, 2014
Background: It is difficult to discern the proportion of blood lead (PbB) attributable to ambient... more Background: It is difficult to discern the proportion of blood lead (PbB) attributable to ambient air lead (PbA), given the multitude of lead (Pb) sources and pathways of exposure. The PbB-PbA relationship has previously been evaluated across populations. This relationship was a central consideration in the 2008 review of the Pb national ambient air quality standards. oBjectives: The objectives of this study were to evaluate the relationship between PbB and PbA concentrations among children nationwide for recent years and to compare the relationship with those obtained from other studies in the literature. Methods: We merged participant-level data for PbB from the National Health and Nutrition Examination Survey (NHANES) III (1988-1994) and NHANES 9908 (1999-2008) with PbA data from the U.S. Environmental Protection Agency. We applied mixed-effects models, and we computed slope factor, d[PbB]/d[PbA] or the change in PbB per unit change in PbA, from the model results to assess the relationship between PbB and PbA. results: Comparing the NHANES regression results with those from the literature shows that slope factor increased with decreasing PbA among children 0-11 years of age. conclusion: These findings suggest that a larger relative public health benefit may be derived among children from decreases in PbA at low PbA exposures. Simultaneous declines in Pb from other sources, changes in PbA sampling uncertainties over time largely related to changes in the size distribution of Pb-bearing particulate matter, and limitations regarding sampling size and exposure error may contribute to the variability in slope factor observed across peer-reviewed studies. citation: Richmond-Bryant J, Meng Q, Davis A, Cohen J, Lu SE, Svendsgaard D, Brown JS, Tuttle L, Hubbard H, Rice J, Kirrane E, Vinikoor-Imler LC, Kotchmar D, Hines EP, Ross M. 2014. The Influence of declining air lead levels on blood lead-air lead slope factors in children. Environ Health Perspect 122:754-760; http://dx.
Building and Environment, 2006
Monitoring of aerosols is typically performed over 3 h to diurnal time scales for outdoor concent... more Monitoring of aerosols is typically performed over 3 h to diurnal time scales for outdoor concentration levels and 15 min to 8 h scales indoors. At these scales, concentration is assumed to be well mixed with little spatio-temporal variability around the sampler. Less attention has been given to the potential for acute exposure to contaminants during the initial minutes after a point-source release, where point-wise concentrations may greatly exceed the well-mixed conditions. Here, we seek to demonstrate that the commonly used well-mixed assumption is flawed in the first minutes after a contaminant is released because point-wise concentration levels are initially highly non-uniform and are influenced by turbulent structures caused by the presence of obstacles in the room. This assumption was examined by releasing 3 mm aerosols in a test room with HEPA filter ventilation and by varying controlled conditions of room furnishings (furnished vs. unfurnished) and contaminant release locations (at the inlet vent or under a desk). For each experiment, aerosol concentrations were measured simultaneously at seven locations by nephelometry. Complementary computational fluid dynamics simulations were performed to lend confidence to the experiments and to provide detailed pictures of the velocity and particle concentration profiles. The experimental and numerical results corroborated the hypothesis. For both release locations in the furnished room, a completely well-mixed condition did not occur 600 s after the release, and aerosol dispersion was dictated by the turbulent airflow pattern. For the empty room, there was significantly less spatial variability in the point-wise measured concentrations after 300 s than for the furnished room. This information may aid in evaluating the potential for occupant exposure to aerosolized hazardous substances and in supporting optimization of detector placement. Published by Elsevier Ltd.
Environmental Health Perspectives, 2013
Background: This paper presents an application of quantitative ion character-activity relationshi... more Background: This paper presents an application of quantitative ion character-activity relationships (QICAR) to estimate associations of human cardiovascular (CV) diseases (CVDs) with a set of metal ion properties commonly observed in ambient air pollutants. QICAR has previously been used to predict ecotoxicity of inorganic metal ions based on ion properties. oBjectives: The objective of this work was to examine potential associations of biological end points with a set of physical and chemical properties describing inorganic metal ions present in exposures using QICAR. Methods: Chemical and physical properties of 17 metal ions were obtained from peer-reviewed publications. Associations of cardiac arrhythmia, myocardial ischemia, myocardial infarction, stroke, and thrombosis with exposures to metal ions (measured as inference scores) were obtained from the Comparative Toxicogenomics Database (CTD). Robust regressions were applied to estimate the associations of CVDs with ion properties. results: CVD was statistically significantly associated (Bonferroni-adjusted significance level of 0.003) with many ion properties reflecting ion size, solubility, oxidation potential, and abilities to form covalent and ionic bonds. The properties are relevant for reactive oxygen species (ROS) generation, which has been identified as a possible mechanism leading to CVDs. conclusion: QICAR has the potential to complement existing epidemiologic methods for estimating associations between CVDs and air pollutant exposures by providing clues about the underlying mechanisms that may explain these associations. key words: air pollution, cardiovascular disease, multipollutant, QICAR, QSAR. Environ Health Perspect 121:558-564 (2013). http://dx.