Citation:

Huber, A H., R. B. Singh, R C. Gilliam, AND J N. Braddock. REAL-TIME MODELING AND MEASUREMENT OF MOBILE SOURCE POLLUTANT CONCENTRATIONS FOR ESTIMATING HUMAN EXPOSURES IN COMMUNITIES NEAR ROADWAYS. Presented at 2000 Annual Meeting of the International Society of Exposure Analysis, Pacific Grove, CA, October 24-27, 2000.

Impact/Purpose:

The research is planned to meet the following objectives:

Support is provided to HEASD Tasks by Alan Huber. (60% 9524 New Air Toxics Modeling, ; 10% 5732 PM Population Exposure Modeling; 10% 3948 Next Generation MMMP Exposure Modeling; 10% N533 PM Toxic agent exposure modeling, and 10% 3957 Integrated Human Exposure Source-to-Dose Modeling)

Development of data and algorithms for exposure modeling in urban areas, to be used in refined probabilistic exposure models being developed elsewhere, to allow prediction of human exposures for an urban population.

Characterize exposures and variability of concentrations in critical microenvironments in urban areas using targeted measurement studies and refined air quality models.

Identify critical human activities influencing exposures, especially identifying microenvironments that are key to exposures to urban air toxics.

Develop methods (measurements, dispersion modeling, receptor modeling) to distinguish exposures to "near field" sources - like indoor sources, human activities or hobbies, or nearby point or area sources - from "background" concentrations or from distant sources that can be modeled well by compartmental or air quality models.

Provide data and algorithms based on a scientific understanding of exposure dynamics for inclusion in NERL human exposure models and other models like OAR's TRIM..

Description:

The United States Environmental Protection Agency's (EPA) National Exposure Research Laboratory (NERL) is pursuing a project to improve the methodology for real-time site specific modeling of human exposure to pollutants from motor vehicles. The overall project goal is to develop improved methods for modeling the source through the air pathway to human exposure in significant microenvironments of exposure. Our developments for microscale modeling refer to spatial scales from the size of an individual vehicle to the order of 1 km.

Current human exposure models using simplified assumptions based on a few fixed air monitoring stations or modeled concentrations from regional-scale motor vehicle emission/transport models have great uncertainty in representing the actual human exposures and should be improved. The first component of the modeling framework is real-time site-specific motor vehicle emission models capable of capturing real-world emissions. Then an urban-scale meteorological and air dispersion model is used to provide ambient air concentrations resulting from transport and other human activities. Refined modeling using Computational Fluid Dynamics (CFD) simulation is being applied to develop refined air dispersion models for linkage to a roadway microenvironmental model. This modeling framework helps in establishing the direct relationships between source-to-exposure specific to the particular exposure microenvironment (e.g., standing by the roadside or actually inside the vehicle, inside the moving vehicle, living nearby a roadway). The complete modeling framework from source-to-exposure together with some measurements carried out in the Research Triangle Park area of North Carolina is shown to be a viable system that can be transferred to other locations both as real-time support for an ongoing human exposure field study or to develop feasible scenarios to build distributions of key parameters for a human exposure model.

Record Details:

Record Type:DOCUMENT( PRESENTATION/ ABSTRACT)

Product Published Date:10/24/2000

Record Last Revised:06/21/2006

Record ID: 59622

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Related Organizations:

Role :OWNER

Organization Name :US ENVIRONMENTAL PROTECTION AGENCY

Organization Name :OFFICE OF RESEARCH AND DEVELOPMENT

Organization Name :NATIONAL EXPOSURE RESEARCH LAB

Organization Name :ATMOSPHERIC MODELING DIVISION