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IDENTIFYING SOURCES OF HUMAN EXPOSURE
Impact/Purpose:
The goal of this task is to develop methods and models to reduce the uncertainty in quantifying the air pollutant source impacts on residential indoor/outdoor and personal samples. A combination of high sensitivity organic and analytical methods, and models will be developed and evaluated to reduce the uncertainty in source apportionment:
(1) Organic analysis methods for low flow samples
(2) Multivariate models for residential indoor and outdoor, and personal samples
(3) Innovative low cost coarse fraction sampling methods.
In addition, this task contributes to two additional tasks that have research focused on reducing the uncertainty in source apportionment: Identifying Local and Regional Sources (21120), and NAAQS Implementation (21179).
Description:
Air pollution from ambient sources continues to adversely impact human health in the United States. A fundamental goal for EPA is to implement air quality standards and regulations that reduce health risks associated with exposures to criteria pollutants and air toxics. However, this is not an easy or straightforward task. The NRC has recommended that research should be conducted to identify those pollutants and sources that are responsible for the most significant risks in air sheds. A critical component of this research is to develop an understanding of how pollutants from sources impact ambient concentrations and, in turn, how these concentrations relate to exposures. This information provides a fundamental linkage for evaluating health impacts and developing effective mitigation strategies.
The Identifying Sources of Human Exposure task is one of two tasks supporting the research area "Reducing Uncertainty in Source Apportionment." It complements Task 21220, Identifying Local and Regional Source Impacts, which supports method and model development for distinguishing local and regional sources and their impacts. The purpose of this task is to develop, evaluate, and apply methods and models that can be used to improve our understanding of how sources impact residential outdoor, indoor, and personal concentrations and, in particular, to identify ambient (sources such as motor vehicles and power plants) source contributions. The task will include analyses of data and modeling results to determine which sampling methods and modeling improvements will likely have the most significant impact in reducing uncertainties in source apportionment analyses. Using insights from these analyses, organic analytical methods will be refined and evaluated. Enhancements to receptor modeling tools will be made that will increase their ability to discern ambient and indoor sources and impacts. In addition, these enhanced models will be applied to the Research Triangle Park (RTP) and DEARS VOC and PM data to demonstrate the increased confidence in the resulting estimates of source contributions to outdoor, indoor, and personal air concentrations. An innovative passive aerosol sampler will also be evaluated to identify and quantify coarse particle sources. Finally, a motor vehicle profile will be developed based on the Kansas City (KC) Dynamometer study samples (low flow near ambient samples collected on Teflon filter media) for future model development and applications. The tools and methods developed in this task will provide scientists and policy makers with information needed to analyze the air pollution sources contributing to human exposure.