Development and Evaluation of Portable Passive and Real-time Measurement Systems, and Dispersion Models, to Estimate Exposure to Traffic-related Air Pollutants PDF Download
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Author: Nicola Masey Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
This research developed efficient applications of portable measurement systems to assess human exposure to traffic-related air pollution through direct measurement, and evaluation of exposure models.Passive NO2 samplers are deployed at large numbers of sites in epidemiological studies to estimate typical concentrations over 1-4 weeks. I found that deployment time could be reduced to 2 days with limited impact on the accuracy and precision of exposure estimates. This shorter measurement time enabled observation of wind-speed effects leading to overestimation of ambient concentrations by passive samplers. Through development of a post-processing technique and/or inclusion of a membrane I improved sampler accuracy. Portable sensors can provide detailed estimates of personal exposures to air pollution. Many sensor-based monitors have not been subject to rigorous testing procedures to quantify their accuracy. I observed that the most accurate estimates of concentrations from NO2 and O3 sensor-based monitors required regular, intermittent calibration against reference analysers under similar environmental conditions to field measurements. I also found deterioration in BC monitor accuracy and precison when the attenuation of the collection filter exceeded 40 and no improvement in monitor accuracy was observed when filter darkness correction algorithms were applied. Portable sensors can be used to identify locations with higher concentrations, which may require more detailed monitoring. I established that repeated 6-minute measurements of BC and particle number concentrations estimated similar spatial trends to 1-week NO2 measurements using passive samplers. Dispersion models can be used to estimate pollution exposure at multiple locations over a study area. I found that initial user parameterisation in a weather model had limited effect on pollution estimates from a dispersion model. I evaluated a new GIS-based dispersion model (5 x 5 m NO2 estimates for a 3,500 km2 area, with model run times of under 10 minutes). I demonstrated that inclusion of discrete street canyon models and geospatial surrogates (accounting for urban morphology) improved model accuracy. The measurement and modelling evaluation research in this thesis complimented each other by providing efficient ways to directly measure population exposures.
Author: Nicola Masey Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
This research developed efficient applications of portable measurement systems to assess human exposure to traffic-related air pollution through direct measurement, and evaluation of exposure models.Passive NO2 samplers are deployed at large numbers of sites in epidemiological studies to estimate typical concentrations over 1-4 weeks. I found that deployment time could be reduced to 2 days with limited impact on the accuracy and precision of exposure estimates. This shorter measurement time enabled observation of wind-speed effects leading to overestimation of ambient concentrations by passive samplers. Through development of a post-processing technique and/or inclusion of a membrane I improved sampler accuracy. Portable sensors can provide detailed estimates of personal exposures to air pollution. Many sensor-based monitors have not been subject to rigorous testing procedures to quantify their accuracy. I observed that the most accurate estimates of concentrations from NO2 and O3 sensor-based monitors required regular, intermittent calibration against reference analysers under similar environmental conditions to field measurements. I also found deterioration in BC monitor accuracy and precison when the attenuation of the collection filter exceeded 40 and no improvement in monitor accuracy was observed when filter darkness correction algorithms were applied. Portable sensors can be used to identify locations with higher concentrations, which may require more detailed monitoring. I established that repeated 6-minute measurements of BC and particle number concentrations estimated similar spatial trends to 1-week NO2 measurements using passive samplers. Dispersion models can be used to estimate pollution exposure at multiple locations over a study area. I found that initial user parameterisation in a weather model had limited effect on pollution estimates from a dispersion model. I evaluated a new GIS-based dispersion model (5 x 5 m NO2 estimates for a 3,500 km2 area, with model run times of under 10 minutes). I demonstrated that inclusion of discrete street canyon models and geospatial surrogates (accounting for urban morphology) improved model accuracy. The measurement and modelling evaluation research in this thesis complimented each other by providing efficient ways to directly measure population exposures.
Author: Sponsored by The Health Effects Institute Publisher: National Academies Press ISBN: 0309037263 Category : Science Languages : en Pages : 703
Book Description
"The combination of scientific and institutional integrity represented by this book is unusual. It should be a model for future endeavors to help quantify environmental risk as a basis for good decisionmaking." â€"William D. Ruckelshaus, from the foreword. This volume, prepared under the auspices of the Health Effects Institute, an independent research organization created and funded jointly by the Environmental Protection Agency and the automobile industry, brings together experts on atmospheric exposure and on the biological effects of toxic substances to examine what is knownâ€"and not knownâ€"about the human health risks of automotive emissions.
Author: D. Bruce Turner Publisher: CRC Press ISBN: 9781566700238 Category : Nature Languages : en Pages : 186
Book Description
This completely updated and revised Second Edition of the popular Workbook of Atmospheric Dispersion Estimates provides an important foundation for understanding dispersion modeling as it is being practiced today. The book and accompanying diskette will help you determine the impacts of various sources of air pollution, including the effects of wind and turbulence, plume rise, and Gaussian dispersion and its limitations. Information is shown in summary graphs as well as in equations. The programs included on the diskette allow you to "get the feel" for the results you'll obtain through the input of various combinations of parameter values. The sensitivity of data to various parameters can be easily explored by changing one value and seeing the effect on the results. The book presents 37 example problems with solutions to show the estimation of atmospheric pollutant concentrations for many situations.
Author: Dongqin Zheng Publisher: Open Dissertation Press ISBN: 9781374667112 Category : Languages : en Pages :
Book Description
This dissertation, "Evaluation and Development of Data Assimilation in Atmospheric Dispersion Models for Use in Nuclear Emergencies" by Dongqin, Zheng, 鄭冬琴, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled EVALUATION AND DEVELOPMENT OF DATA ASSIMILATION IN ATMOSPHERIC DISPERSION MODELS FOR USE IN NUCLEAR EMERGENCIES Submitted by Zheng Dongqin for the degree of Doctor of Philosophy at The University of Hong Kong in August 2007 When radioactive contaminants are released into the atmosphere during a nuclear accident, the consequence assessment that relies on atmospheric dispersion models plays an important role for the decision-makers in taking the correct response. In this thesis, a 3D Monte Carlo Dispersion Model (MCDM) was developed and evaluated. Data assimilation technique was in- corporated to give a real time consequence assessment in the unlikely event of a nuclear accident of the nuclear power plant (NPP) in the Daya Bay. The predictions of MCDM were compared with that of the Particle Dis- persion Model (PDM) developed by the Hong Kong Observatory. The dif- ferences in air concentrations and ground depositions predicted by the two models were found to be within one order of magnitude. MCDM predictions were also tested against the measurements of a eld dispersion of radioactivematerials from a research reactor in Mol, Belgium. Both the gamma uence rates and the plume geometry given by MCDM are comparable with the measurement results. Although the dispersion model can execute well given a known source term, meteorological data and dispersion parameters, uncertainties of these model parameters may inuence the reliability of model predictions. The ability of a model in assimilating measurement data is crucial to improve model predictions. In this thesis, a data assimilation method based on the Ensemble Kalman Filter (EnKF) and a stochastic nonlinear state space model was proposed. It presents a new method for online update of the model predictions and estimation of the model parameters, i.e. the release rate, wind direction, or turbulence intensity, by adding the measurement in- formation. The proposed method has been tested by twin experiments in which simulated ground level dose rates have been assimilated. The predic- tion errors caused false' estimations of model parameters could be reduced by more than 60%. The temporal variations of model parameters estimated by EnKF were found to follow the true' value very well. In order to test the data assimilation method with real experimental data, a wind tunnel dispersion experiment was carried out for the east and south-east wind directions over the area surrounding the Daya Bay NPP. The measurement data collected were assimilated in the dispersion model. Amethodwaspresentedbyusingrandomeldstoconstructtheerrorsin3D parameters, e.g. the wind direction and turbulence intensity. This method is very helpful in ensuring the performance of the EnKF. The data assimilation method was also tested against the Mol experi- mental data. The gamma uence rates overestimated by the MCDM were corrected by EnKF. The temporal variations of model parameters estimated by EnKF have been shown to provide useful information for tracking the major error sources. DOI: 10.5353/th_b3934603 Subjects: Radioactive fallout Particle size determination Monte Carlo method
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
This paper describes a new 3-D multi-scale atmospheric dispersion modeling system and its on-going evaluation. This system is being developed for both real-time operational applications and detailed assessments of events involving atmospheric releases of hazardous material. It is part of a new, modernized Department of Energy (DOE) National Atmospheric Release Advisory Center (NARAC) emergency response computer system at Lawrence Livermore National Laboratory. This system contains coupled meteorological data assimilation and dispersion models, initial versions of which were described by Sugiyama and Chan (1998) and Leone et al. (1997). Section 2 describes the current versions of these models, emphasizing new features. This modeling system supports cases involving both simple and complex terrain, and multiple space and time scales from the microscale to mesoscale. Therefore, several levels of verification and evaluation are required. The meteorological data assimilation and interpolation algorithms have been previously evaluated by comparison to observational data (Sugiyama and Chan, 1998). The non-divergence adjustment algorithm was tested against potential flow solutions and wind tunnel data (Chan and Sugiyama, 1997). Initial dispersion model results for a field experiment case study were shown by Leone et al. (1997). A study in which an early, prototype version of the new modeling system was evaluated and compared to the current NARAC operational models showed that the new system provides improved results (Foster et al., 1999). In Section 3, we show example results from the current versions of the models, including verification using analytic solutions to the advection-diffusion equation as well as on-going evaluation using microscale and mesoscale dispersion field experiments.
Author: IARC Working Group on the Evaluation of Carcinogenic Risks to Humans Publisher: IARC Monographs on the Evaluat ISBN: 9789283201472 Category : Medical Languages : en Pages : 0
Book Description
"This publication represents the views and expert opinions of an IARC Working Group on the Evaluation of Carcinogenic Risk to Humans, which met in Lyon, 8-15 October 2013."
Author: Nataliya Mykhaylova Publisher: ISBN: Category : Languages : en Pages :
Book Description
The exposure to air pollutant mixtures is a well-known risk factor for inducing and increasing the severity of diseases. Combining low-cost sensors in arrays holds great potential for real-time monitoring of pollutant exposure because of versatility and aptitude for tracking multi-pollutant exposure. While many low-cost air pollution monitoring devices have been proposed, several underexplored opportunities remain, including sensor-derived pollution indices, source analysis and exposure assessment. A thorough investigation of different low-cost commercial gas and particulate matter sensors from 5 manufacturers has been conducted and best-performing sensors were identified. A device for monitoring air quality has been developed and tested. Each device consists of an array of commercially available metal oxide semiconductor for monitoring NOx and O3, CO, CO2 and optical sensors for monitoring PM2.5. Level of pollutant exposure has been characterized at different locations in Toronto over 3 different campaigns between 2013 and 2016. These deployments allowed long-term sensor performance to be evaluated under different meteorological conditions as well as different ranges of pollutant concentrations. Analysis of a large range of gas sensors revealed several key challenges, including high intra-sensor variability, interference from temperature and nonlinearity. Air quality health index estimation from sensor readings was successfully demonstrated. Three aspects of device reproducibility were evaluated: drift over time, impact of interferences and impact of site-specific mixtures. Three categories of approaches for improving sensor accuracy and reproducibility were tested: nonlinear calibration models, variable transformations and training data selection. Model reproducibility, ability to adjust for multiple combinations of interferences and ability to resolve sites was improved when devices were calibrated at multiple sites. Analysis showed that both short-term and long-term temporal patterns could be resolved and compared at different sites. Background subtraction helped further emphasize the differences and rank sites in terms traffic-related pollution.
Author: National Research Council Publisher: National Academies Press ISBN: Category : Medical Languages : en Pages : 553
Book Description
Discusses pollution from tobacco smoke, radon and radon progeny, asbestos and other fibers, formaldehyde, indoor combustion, aeropathogens and allergens, consumer products, moisture, microwave radiation, ultraviolet radiation, odors, radioactivity, and dirt and discusses means of controlling or eliminating them.
Author: Nicola Masey
Author: Nicola Masey
Author: Sponsored by The Health Effects Institute
Author: D. Bruce Turner
Author: Dongqin Zheng
Author: 
Author: 
Author: Karl B. Schnelle
Author: IARC Working Group on the Evaluation of Carcinogenic Risks to Humans
Author: Nataliya Mykhaylova
Author: National Research Council