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MODELING ENVIRONMENTAL EXPOSURES TO PARTICULATE MATTER AND PESTICIDES
Citation:
Ozkaynak, A H. MODELING ENVIRONMENTAL EXPOSURES TO PARTICULATE MATTER AND PESTICIDES. Presented at International Meeting on Particulate Matter Exposures and Health Effects, London, United Kingdom, June 25-July 3, 1999.
Description:
This presentation describes initial results from on-going research at EPA on modeling human exposures to particulate matter and residential pesticides. A first generation probabilistic population exposure model for Particulate Matter (PM), specifically for predicting PM1o and PM2.5 exposures of an urban population has been developed. This model is intended to be used to (predict exposure (magnitude, frequency, and duration) of the general population and susceptible subpopulations to PM of ambient origin. Two-stage Monte-Carlo simulation techniques are used to characterize uncertainty and variability in the various model parameters and inputs. The model has been applied to Vancouver, Canada, following the statistical spatial interpolation of the ambient PM10 data to predict the distributions of PM exposures by cohort, age, activity type and microenvironment category. Results show wide ranges in the predicted personal exposures of various population cohorts which are influenced by the different human activities and the I contributions from indoor sources, such as smoking or cooking. A probabilistic model of individual exposure to chlorpyrifos has been developed in support of the US EPA's National Human Exposure Assessment Survey (NHEXAS) and the Food Quality Protection Act (FQPA) program. The model examines a variety of pathways to estimate the contribution of different exposure routes (ingestion, inhalation, dermal contact) and media (soil, dust, air, water, food and residues of pesticides on surfaces following application) to chlorpyrifos exposure. The model predicts exposures for individuals of all ages residing in the state of Arizona and children in the Minneapolis- St. Paul area between the ages of 2 and 12. Preliminary model results show that non-acute (i.e. in the absence of recent applications) exposures to chlorpyrifos are most influenced by the dietary exposure pathway. The youngest age group is shown to have the highest potential exposures. In comparison, predicted acute and short-term (i.e. following recent application) residential exposures and dose from chlorpyrifos residues could be many times greater than the non-acute exposure values, depending on the type of residential pesticide application and the activities of the children. Both the variability and uncertainty in the predicted exposures are found to be very high.
This work has been funded in part by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication.