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DEVELOPMENT OF A MICROSCALE EMISSION FACTOR MODEL FOR CO (MICROFACCO) FOR PREDICTING REAL-TIME VEHICLE EMISSIONS

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Citation:

Singh, R. B. AND A H. Huber. DEVELOPMENT OF A MICROSCALE EMISSION FACTOR MODEL FOR CO (MICROFACCO) FOR PREDICTING REAL-TIME VEHICLE EMISSIONS. Presented at Emission Inventory: Regional Strategies for the Future, Raleigh, NC, October 26-28, 1999.

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 National Exposure Research Laboratory has initiated a project 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 microenvironments of exposure. The PART models (used in the United States, except California) and EMFAC models (used in California only) used to estimate emissions are suitable only for regional (county) scale modeling and emission inventories because of their dependence on aggregated vehicle-miles-traveled data. These emission models are not designed to estimate real-time emissions needed for human exposure studies near roadways. Therefore, there is a need to develop site-specific real-time emission factor models for PM emissions.

    A microscale emission factor model for predicting site-specific real-time motor vehicle particulate matter (MicroFacPM) emissions for TSP, PM10 and PM2.5 has been developed. It uses site-specific available information on the vehicle fleet composition. The algorithm used to calculate emission factors in MicroFacPM is disaggregated based on the site-specific vehicle fleet. The emission factors are calculated from a real-time fleet, rather than from a fleet-wide average estimated by a vehicle-miles-traveled weighting of the emission factors for different vehicle classes. MicroFacPM requires input information necessary to characterize the site-specific real-time fleet being modeled. Other variables required are average vehicle speed, time and day of the year, ambient temperature and relative humidity.

    Record Details:

    Record Type:DOCUMENT( PRESENTATION/ ABSTRACT)
    Product Published Date:10/26/1999
    Record Last Revised:06/21/2006
    Record ID: 60558