The 130th Annual Meeting of APHA

Abstract #41844

Devon Payne-Sturges, MPH, Office of Policy National Center for Environmental Economics, U.S. EPA, Ariel Rios Bldg. MC1809, 1200 Pennsylvania Ave., NW, Washington, DC 20460, 202 260-6016, payne-sturges.devon@epa.gov

Often surrogates for human exposure such as regional ambient air quality data, either measured at air monitoring stations or modeled concentrations, are used to estimate cancer and noncancer risk. The suitability of modeled ambient air quality data as estimators of human exposure was evaluated by comparing the results of a community-based exposure study to exposure estimates based on recent air toxics modeling conducted under EPA's National-Scale Air Toxics Assessment project (NSATA). Comparison between ASPEN Model and actual exposure monitoring showed that ambient pollutant concentrations as surrogates for human exposure generally underestimated personal exposures and their risks. When risks to individual pollutants were aggregated to estimate cumulative risk, the modest underestimation by ASPEN model resulted in significant underestimation of cumulative cancer risk. Average cumulative cancer risk, based on personal exposures, was 141 E -6 as compared to 38 E-6 based on ASPEN modeled concentrations. Both ASPEN and actual personal monitoring identified, chloroform, benzene and carbon tetrachloride as major cancer risk drivers. However, the proportions of cumulative risk were quite different. As compared to personal exposures, the ASPEN model over estimated the relative contributions of benzene (55% versus 23%), and carbon tetrachloride (34% versus 8%) and underestimated chloroform (6% versus 63%). These findings suggest that policies to reduce public health risk to VOCs may be misdirected if solely based on ambient VOC concentrations. Therefore, limited personal exposure monitoring should be conducted to validate models to estimate exposure that might have wider applications.

Learning Objectives: At the conclusion of the session, the participants will be able to

• Identify short-comings of exposure surrogates often used in air pollution risk assessments
• Describe a personal inhalation exposure monitoring method
• Assess health risks associated with exposures to air toxics.

Keywords: Environmental Exposures, Risk Assessment

Presenting author's disclosure statement:
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.