Center for Clean Air Research

Project Title: Exposure mapping – characterization of gases and particles for exposure assessment in health effects and laboratory studies

Investigators: Michael Yost (Project PI), Timothy Larson, Christopher Simpson, Thomas Jobson, Timothy VanReken

Institutions: University of Washington, Seattle, WA; Washington State University, Pullman, WA

Objectives

Roadway-source air pollutants encompass a diversity of chemicals, including both particulate and gas phase components which are transformed by chemical and physical reactions as they age in the environment. Consequently, human exposures to air pollutants can range from relatively un-aged to highly aged components that vary with respect to particle size and the chemical composition of particle and gas phase components. This proposal is will employ mobile and fixed site monitoring to assess both gas and particle components of these pollutants as they age from roadway sources to population areas, for a more comprehensive understanding of the seasonal and spatial variability in the concentration and composition of air pollutant exposures within MESA-Air cities. The main project objectives are: (1) Characterize spatial and temporal gradients of selected air pollutants along roadways and within neighborhoods in MESA cities using a mobile platform; (2) Measure spatial variation in concentrations of selected air pollutants at two-week average fixed sites in coordination with the mobile measurements. (3) Characterize aging of air pollutant components transported from roadway sources to neighborhood receptor locations; and (4) Provide detailed characterization of laboratory exposure conditions available for toxicology testing, and identify likely conditions that mimic those found in urban settings.

Approach

We will (1) use mobile monitoring with an instrument platform designed to measure concentrations of particles and gases while continuously on the move. These data will be used by the Biostatistics Core to develop multivariate spatial models of selected roadway-source air pollutants for use in health studies, and to characterize the aging of air pollutant components as they are transported from sources to populated areas; (2) use passive monitoring at approximately 20 stationary sites in each of the four MESA cities to measure concentrations of coarse particles, gases (O3, SO2, NO, NO2), and selected volatile organic compounds (VOCs). These measurements will be used in conjunction with the mobile measurements to develop multivariate spatial models of selected roadway-source air pollutants; (3) characterize the laboratory exposure conditions available for toxicology testing, and identify likely conditions that mimic those found in urban settings. This will be achieved by deploying the same instruments used in the mobile monitoring platform, along with LRRI instruments and additional high sensitivity mass-spectrometer instruments only available for the laboratory facilities (Aerosol TOF-MS for particles and PTR-MS for VOCs).

Expected Results

1. Develop multivariate spatial models of selected roadway source air pollutants for use in health studies.
2. Characterize the aging of roadway source air pollutant components as they are transported from sources to populated areas.
3. Characterize the laboratory multi-pollutant atmospheres for toxicology testing, to help describe physical and chemical transformation processes occurring in the laboratory and to help determine the comparability of conditions generated by in the laboratory to those observed in the field.

Supplemental Keywords: exposure science, community exposures, chemical transport