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Modeling and Evaluation of Mechanisms Controlling the Outdoor/Indoor Relationships of Fine Particle Levels and Characteristics

EPA Grant Number: R826768
Title: Modeling and Evaluation of Mechanisms Controlling the Outdoor/Indoor Relationships of Fine Particle Levels and Characteristics
Investigators: Georgopoulos, Panos G.
Current Investigators: Georgopoulos, Panos G. , Isukapalli, Sastry S. , Jayjock, Eric , Sun, Qing
Institution: University of Medicine and Dentistry of New Jersey
Current Institution: Environmental and Occupational Health Sciences Institute
EPA Project Officer: Shapiro, Paul
Project Period: October 1, 1998 through September 30, 2000
Project Amount: $170,828
RFA: Air Pollution Chemistry and Physics (1998)
Research Category: Engineering and Environmental Chemistry

Description:

Objectives/Hypotheses: In the recent report by the National Research Council on "Research Priorities for Airborne Particulate Matter" (National Academy Press, 1998) the first research topic (p.46) is identified as "Outdoor Measures vs. Actual Human Exposures". It is specifically stated (p.49) that "[p]ollutant concentrations in outdoor air often are very different from actual personal exposures. Understanding the relationship between particulate-matter mass concentrations measured at fixed outdoor sites and actual human exposure to particulate matter will help guide and improve decisions about ambient pollution control strategies." In the same chapter it is also recognized (p.48) that "the investigation of relationships between actual personal exposures and outdoor air-particle concentrations is crucial for validating and interpreting the results of epidemiological studies [...]". Along the lines of the priorities identified in the above report, the objective of this project is to study and enhance our mechanistic understanding of the factors controlling the outdoor/indoor relationships of various attributes of airborne particulate, including mass and number concentration, size distribution, chemical composition, etc., for various types of human activities and indoor sources.

The proposed work is based on the hypothesis that the factors affecting exposures to particulate matter indoors due to multiple sources (indoor/outdoor) and multiple pathways, can be better understood and quantified through the combined use of state-of-the-art models and databases, that link information for indoor and outdoor aerosols. Approach: The project hypothesis will be tested via the implementation, application, evaluation and iterative refinement of a modular but integrated, modeling system for the mechanistic (i.e. based on fundamental physicochemical principles) description of particulate matter processes. This effort will utilize existing comprehensive field ("real home") measurements collected in a recent field study that was conducted in the Boston metropolitan area by researchers from the Harvard School of Public Health (HSPH). Separate components of the HSPH database will be used to derive values for various model inputs and parameters and for testing/evaluating individual model components. The model evaluation tasks will take place in collaboration and interaction with the HSPH group that performed the experimental study. The mathematical/algorithmic and computational tools necessary to develop and implement the proposed project have been under continuing development and refinement by the project team over the last five years and will be designed so as to be compatible with models for ambient (outdoor) aerosol processes.

Improvement in Risk Assessment or Risk Management: Improved tools for characterizing indoor attributes of airborne particulate matter, and their relationships to the corresponding outdoor characteristics, could provide both improved quantitative estimates of human exposures and doses for "real world" conditions and a better mechanistic understanding of these exposures. To quote the above mentioned 1998 National Research Council Report (p.49), "understanding the origin and composition of such exposures is of paramount importance for developing and implementing risk- reduction strategies [...] by determining the contributions of different sources to personal exposures, as well as by investigating how these contributions are influenced by patterns of personal activity."

Expected Results:

This project will lead to the development and implementation (application and testing) of a state-of-the-art computational modeling system that will allow for the calculation of concentration, composition, and size distribution of airborne particulate matter indoors by accounting for influx of polluted outdoor air and for the presence of indoor sources. Specific computational modules will be developed and tested for simulating the processes of aerosol emission or formation, growth, coagulation and deposition in the indoor environment. G and aerosol phase chemistry will be coupled in this system. These modeling tools could be used : (1) to quantify the mechanisms leading to differences in PM levels indoors compared to outdoor measurements, and (2) to provide detailed characterization of indoor particulate matter attributes (mass/number size distribution, chemical composition), which affect actual human exposures and corresponding delivered doses.

Publications and Presentations:

Publications have been submitted on this project: View all 8 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 2 journal articles for this project

Supplemental Keywords:

indoor air aerosols, indoor air modeling, total human exposure , Air, Geographic Area, Scientific Discipline, Health, RFA, indoor air, Risk Assessments, Physics, Health Risk Assessment, Atmospheric Sciences, particulate matter, East Coast, aerosols, ambient air quality, indoor air quality, multiple pathways, Region1, Boston, Massachusetts, ambient pollution control strategies, home, particulates, atmospheric chemistry, modeling studies, exposure, ambient pollution control, indoor air chemistry, ambient aerosol, human exposure

Progress and Final Reports:
Final Report

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.

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