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REAL-TIME MODELING OF MOTOR VEHICLE EMISSIONS FOR ESTIMATING HUMAN EXPOSURES NEAR ROADWAYS

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http://cfpub.epa.gov/si/si_public_comments.cfm

Citation:

Singh, R. B., A H. Huber, AND J N. Braddock. REAL-TIME MODELING OF MOTOR VEHICLE EMISSIONS FOR ESTIMATING HUMAN EXPOSURES 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 is developing a real-time model of motor vehicle emissions to improve the methodology for modeling human exposure to motor vehicle emissions. The overall project goal is to develop improved methods for modeling the source through the air pathway to human exposure in significant roadway related microenvironments of exposure. Current motor vehicle emission (for example, EPA MOBILE and PART) models are designed to estimate regional (county) scale emission factors, and emission inventories based on vehicle miles traveled. These models are not reliable for real-time and site-specific locations needed to support studies of human exposure. In view of the above, a real-time microscale automobile emission factor model for CO (MicroFacCO) and PM (MicroFacPM) are being developed. These models are designed to use all the information that has been developed for United States vehicles. This paper demonstrates the application and the sensitivity of emission estimates from these models to real-time input parameters for vehicle fleet composition, vehicle speed and meteorological conditions. The emission rates calculated from these models are used in conjunction with a roadway air dispersion model to estimate the ambient concentrations near roadways for a range of traffic fleet and meteorological conditions. The modeled results show that the real-time site-specific on-road traffic fleet and micrometeorology play an important role in the estimation of ambient concentrations. Therefore, real-time site-specific motor vehicle emissions and micrometeorology should be made an integral part of the human exposure assessments.

    Record Details:

    Record Type:DOCUMENT( PRESENTATION/ ABSTRACT)
    Product Published Date:10/24/2000
    Record Last Revised:06/21/2006
    Record ID: 59623