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NEW APPLICATION OF PASSIVE SAMPLING DEVICES FOR ASSESSMENT OF RESPIRATORY EXPOSURE TO PESTICIDES IN INDOOR AIR
Citation:
Lewis, R. G., D M. Stout II, C. R. Fortune, AND W. D. Ellenson. NEW APPLICATION OF PASSIVE SAMPLING DEVICES FOR ASSESSMENT OF RESPIRATORY EXPOSURE TO PESTICIDES IN INDOOR AIR. Presented at Pittcon 2002, New Orleans, LA, March 17-22, 2002.
Impact/Purpose:
1. To identify those pesticides, pathways, and activities that represent the highest potential exposures to children;
2. To determine the factors that influence pesticide exposures to children;
3. To develop methods for measuring multimedia exposures to children, including methods that account for important activities that take place in home, school, and day care settings;
4. To generate data on multimedia pesticide concentrations, pesticide biomarkers, and exposure factors that can be used as inputs to aggregate exposure models for children.
Description:
The United States Environmental Protection Agency (EPA) has long maintained an interest in potential applications of passive sampling devices (PSDs) for estimating the concentrations of various pollutants in air. Typically PSDs were designed for the workplace monitoring of volatile organic compounds (VOCs) in ambient air. Their utility was found to be limited by interferences encountered during analysis and inadequate sensitivity. A thermally-desorbable diffusive sampling device with high sensitivity for VOCs was developed, but saw little use outside of EPA. Subsequently, the EPA and Harvard University modified the Ogawa 3300 diffusive sampler (originally designed for the collection of ozone) for the purpose of collecting organic compounds. Until recently, however, there has been little interest in the application of passive sampling for organic compounds in ambient and indoor air.
Approaches for indoor residential air monitoring pose unique considerations associated with participant objections to sampling equipment noise, an increased potential of equipment tampering, and the lack of available space for the placement of sampling equipment. PSDs might present viable alternatives for estimating respiratory exposures inside occupied homes. Furthermore, unlike active samplers, PSDs may be deployed for days, weeks, or months to obtain integrated exposure estimates with little burden to the occupant. Of particular interest are indoor pollutants, such as pesticides, which fall into the semivolatile category (vapor pressures between 10-2-10-8 kPa at 25 degrees C). Semivolatile pesticides are primarily present in indoor air as vapors and may be collected by diffusion onto a sorbent or by gas-sorbent partitioning. Based on these sampling principles, PSDs might be efficiently deployed in residential settings to sample a variety of indoor pollutants, determine estimates of respiratory exposures and to conduct screening levels surveys, while placing little burden on the occupants.
Currently several different types of PSDs are undergoing evaluations by the EPA to determine their usefulness for the collection of pesticide vapors from indoor air. Included are traditional diffusion-controlled PSDs such as the EPA VOC device, the Ogawa 3300, and European radial diffusers. The EPA has also collaborated with the United States Geological Survey to help evaluate semipermeable membrane devices and with Midwest Research Institute to test a simple gas-sorbent partitioning sampler.
This work has been funded wholly or in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.