Grantee Research Project Results

2012 Progress Report: Exposure Mapping – Characterization of Gases and Particles for ExposureAssessment in Health Effects and Laboratory Studies

EPA Grant Number: R834796C001
Subproject: this is subproject number 001 , established and managed by the Center Director under grant R834796
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: University of Washington Center for Clean Air Research
Center Director: Vedal, Sverre
Title: Exposure Mapping – Characterization of Gases and Particles for ExposureAssessment in Health Effects and Laboratory Studies
Investigators: Yost, Michael , Larson, Timothy V. , VanReken, Timothy M. , Simpson, Chris , Jobson, B. Thomas
Current Investigators: Yost, Michael , VanReken, Timothy M. , Jobson, B. Thomas , Larson, Timothy V. , Simpson, Chris
Institution: University of Washington , Washington University
EPA Project Officer: Callan, Richard
Project Period: December 1, 2010 through November 30, 2015 (Extended to November 30, 2017)
Project Period Covered by this Report: December 1, 2011 through November 30,2012
RFA: Clean Air Research Centers (2009) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Air

Objective:

Roadway-source air pollutants encompass a diversity of chemicals, including both particulate and gas phase components that 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. To obtain a more comprehensive understanding of the seasonal and spatial variability in the concentration and composition of air pollutant exposures within MESA-Air cities, we 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.

The main project objectives are:

Characterize spatial and temporal gradients of selected air pollutants along roadways and within neighborhoods in MESA cities using a mobile platform.
Measure spatial variation in concentrations of selected air pollutants at 2-week average stationary sites in coordination with the mobile measurements.
Characterize aging of air pollutant components as they are transported from roadway sources to neighborhood receptor locations.
Provide detailed characterization of laboratory exposure conditions available for toxicology testing, and identify likely conditions that mimic those found in urban settings.

Progress Summary:

Aims 1 and 2 continue as the main focus of activities in this year 2 time period. This phase of the study is conducting field sampling through 2013 across four cities in the MESA-Air cohort: Minneapolis/St. Paul, MN; Baltimore, MD; Los Angeles, CA; and Winston-Salem, NC. The instrument platform for mobile monitoring was assembled and tested in Seattle in October of 2011. Heating season measurements have been completed in Minneapolis/St. Paul and Baltimore; non-heating season measurements are completed in Baltimore and are under way in St. Paul. During each 2-week sampling period, the mobile monitoring platform measures concentrations of particles and gases while continuously on the move along a fixed sampling route with position information simultaneously logged by a real-time GPS. Data collection includes the following components: optical particle size in 31 size bins from 10 to 0.2 μm, particle mean diameter and particle count from 0.03 to 0.2 μm, total particle count >0.1 μm, particle light scattering coefficient, particle light absorption (black carbon), NO/NO₂, O₃, CO, CO₂ and total VOCs.

Pre-planned driving routes are created for each city, arranged into three sectors with 14 measurement intersection waypoints in each sector for measurement, plus a common central reference site. These 43 waypoints are selected in advance, based on a set of route criteria developed in consultation with the Biostatistics Core of the center. The routes are evaluated by the Biostatistics Core for use in the spatial mapping of exposures later in the study. These same waypoints coincide with placement of passive sampling devices deployed at the same time as the mobile monitoring. Figure 1 below illustrates the data collected from the winter sampling campaign in St. Paul.

Figure 1 – Ozone Data Collected During Heating Season St. Paul, MN

Quintiles of Ozone data were collected at 43 locations over the heating season in Minneapolis/St. Paul from mobile monitoring and passive sampling. The data represent the average at each location over the 2-week sample period. Reasonable agreement is found between the two types of measurements. Note that the mobile data only are collected during the evening commute, while the passive badges collect continuously over the 2-week period.

In pursuance of Objective 4, detailed chemical characterization measurements were made of controlled exposure atmospheres at LRRI in May 2012. Over the course of 3 weeks, nearly 50 distinct exposure atmospheres were sampled. The majority of these test atmospheres were composed of unaged gasoline and diesel exhaust at various loadings and degrees of mixing; a few atmospheres were also sampled where the emissions were photochemically aged prior to sampling. All test atmospheres were sampled by the same instrument platform used for the mobile sampling. Additionally, the WSU collaborators sampled the test atmospheres with a high resolution time-of-flight aerosol mass spectrometer (HR-AMS) and a proton transfer reaction mass spectrometer (PTR-MS). The PTR-MS was coupled with a thermal desorption system for analyzing organic compounds with intermediate volatility. The HR-AMS and PTR-MS provided a much more detailed characterization of the particle- and gas-phase organic composition of the test atmospheres, which will yield improved understanding of the chemical characteristics and phase partitioning behavior of exhaust mixtures. Preliminary results from the experiments at LRRI were presented at the CLARC annual meeting. Detailed analysis is ongoing, and multiple publications and presentations are expected in the coming year.

Relatively few problems have been encountered to date that have required any modifications in the project aims. After consulting with the Biostatistical Core, we determined that more passive samplers were needed to provide an adequate description of spatial variability in pollutants, and to reflect study subject residence concentrations. The main change has been to expand the number of passive samplers from 20 to 43 in each city. A standardized vehicle platform also was needed to improve logistics of the field sampling and to improve data QC. We attempted to use a hybrid vehicle to enable a more accurate measurement of roadway pollutants in traffic. However, this was not possible because most rental companies either do not offer a hybrid or have very few available. The same make/model vehicle (Ford Escape) is rented in each city during the measurement sessions.

Because of funding limitations associated with MESA Air and Project 5, epigenetic analyses are only available from a subset of the originally proposed MESA Air cities (See Project 5 Summary). As a result, both Project 5 and Project 1 altered their sample design to conduct air monitoring in the current four cities: St. Paul, Baltimore, Winston-Salem and Los Angeles, while dropping New York and Chicago. This change, although not ideal with respect to epigenetics, does provide opportunities for monitoring increased pollutant concentrations in Los Angeles and more comprehensive participant health measurement.

Future Activities:

Activities in the next year will focus on completing the field sampling campaigns and assembling the data set for further analysis. We have completed most of the field work for the current year and are on target to complete half of the field sampling by the fall of 2012. Additionally, we scheduled field work for Los Angeles and Winston-Salem and established the mobile monitoring routes for these cities. We also have scheduled the chamber characterization studies in Seattle/UW for next year. Data cleaning and QC review are under way for the cities that already have been sampled, and we are working with the Biostatistics core to automate the data QC process. Work on publications and dissemination of results for the first year of measurements will follow soon after the data set is ready. We anticipate starting the second year of field measurements in January and continuing over the next year, which will be similar to field deployments this past year.

Journal Articles:

No journal articles submitted with this report: View all 43 publications for this subproject

Supplemental Keywords:

exposure science, community exposures, chemical transport, mobile monitoring, Scientific Discipline, Health, Air, ENVIRONMENTAL MANAGEMENT, Air Quality, air toxics, Health Risk Assessment, Risk Assessments, mobile sources, Environmental Monitoring, Biochemistry, Atmospheric Sciences, Risk Assessment, ambient air quality, atmospheric particulate matter, particulate matter, aerosol particles, air pollutants, motor vehicle emissions, vehicle emissions, air quality models, motor vehicle exhaust, airway disease, bioavailability, air pollution, particle exposure, atmospheric aerosols, ambient particle health effects, vascular dysfunction, cardiotoxicity, atmospheric chemistry, exposure assessment

Progress and Final Reports:

Original Abstract

Main Center Abstract and Reports:

R834796 University of Washington Center for Clean Air Research

Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R834796C001 Exposure Mapping – Characterization of Gases and Particles for ExposureAssessment in Health Effects and Laboratory Studies
R834796C002 Simulated Roadway Exposure Atmospheres for Laboratory Animal and Human Studies
R834796C003 Cardiovascular Consequences of Immune Modification by Traffic-Related Emissions
R834796C004 Vascular Response to Traffic-Derived Inhalation in Humans
R834796C005 Effects of Long-Term Exposure to Traffic-Derived Particles and Gases on Subclinical Measures of Cardiovascular Disease in a Multi-Ethnic Cohort

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