2013 Progress Report: Effects of Long-Term Exposure to Traffic-Derived Particles and Gases on Subclinical Measures of Cardiovascular Disease in a Multi-Ethnic Cohort

EPA Grant Number: R834796C005
Subproject: this is subproject number 005 , 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: Effects of Long-Term Exposure to Traffic-Derived Particles and Gases on Subclinical Measures of Cardiovascular Disease in a Multi-Ethnic Cohort
Investigators: Vedal, Sverre , Kaufman, Joel D. , Larson, Timothy V. , Sampson, Paul , Sheppard, Lianne (Elizabeth) A. , Szpiro, Adam , Yost, Michael
Current Investigators: Kaufman, Joel D. , Larson, Timothy V. , Sampson, Paul , Sheppard, Lianne (Elizabeth) A. , Szpiro, Adam , Vedal, Sverre , Yost, Michael
Institution: University of Washington
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, 2012 through November 30,2013
RFA: Clean Air Research Centers (2009) RFA Text |  Recipients Lists
Research Category: Health Effects , Air

Objective:

Project 5 has three primary objectives, which are unchanged from those described previously:
  1. Employ the small-scale gradient data acquired as part of the mobile monitoring campaign in Project 1, in conjunction with central fixed site data, regulatory monitoring data, and geographic covariates, to build a multi-pollutant exposure model for traffic-derived air pollutants. This model will incorporate complex spatial information on primary and secondary traffic-derived particles and gases.
  2. Develop and validate individual-level exposure estimates for traffic-derived air pollutants, integrating: i) the outdoor residential concentration estimates from the multi-pollutant model; ii) estimates of residential infiltration rates; iii) road class- and traffic condition-specific estimates of on-roadway concentrations; and iv) individual-level questionnaire-derived time location information. These individual-level exposure estimates also will utilize personal monitoring data designed to clarify the in-transit component of total exposure.
  3. Estimate the effect of individual-level exposure to traffic-derived air pollution on subclinical cardiovascular disease using these exposure models. Health outcomes will  include left ventricular myocardial mass as ascertained by MRI, arteriolar diameters as measured by retinal photography, coronary artery calcium as ascertained by CT, intima-medial thickness as measured by ultrasound, and DNA methylation.

Progress Summary:

Over the past year, we have focused our efforts on the field work portion of this project, which will address signification portions of the second aim of this project. Specifically, through a combination of personal, residential and in-vehicle sampling, paired with intensive location tracking, we intend to understand the influence of time spent in transit on personal exposure, which will improve our individual-level exposure estimates and contribute to our epidemiological analysis.
 
The field work component of this project is planned to occur twice in two seasons each in Winston-Salem and Los Angeles, and involves individual-level air monitoring in multiple microenvironments, GPS tracking over a relatively long duration, and proximity monitoring, each of which required unique methods for novel equipment development. Specifically, we have designed and built in-vehicle passive monitoring devices that capture exposures during driving. We also have designed and built proximity monitors, which record time spent in specific microenvironments (inside the residence and inside the vehicle), and we have customized off-the-shelf GPS units to allow continuous location tracking for periods up to and exceeding 2 weeks.
 
All of this equipment was tested during a series of pilot studies. In the first pilot study, we evaluated the ability of an external battery, connect to GPS units through a customized circuit board, to provide sufficient data acquisition, data quality, and sampling duration. This configuration was successful and we determined that we could track participant locations continuously for up to a month. During a second pilot study, we evaluated the custom-built in-vehicle samplers, which consist of a stainless steel container fitted with a Teflon core and Ogawa and 3M VOC passive sampling badges. Our aims for this pilot study were to determine how much driving time was required to meet sample detection limits, to evaluate sample reproducibility, and to ensure that the equipment did not leak (i.e., that blank samples were, in fact, blank). This pilot study occurred in December of 2012, and included 20 samples (10 sets of duplicates). We observed generally high reproducibility among duplicates, low concentrations in blanks, and determined that detection limits were reliably exceeded in samples of participants with driving times of 30 minutes/day or greater over a 2-week period. We also observed that our measured concentrations were consistent with those observed in previous studies. A second pilot study was conducted in March of 2013 to ensure that the Teflon cores we were using were not acting as “sinks” for the pollutants, and these results taken together have provided confidence in our equipment.
 
Figure 1, below, shows the relationship between driving time (during which the samplers were open) and absolute mass (µg) of NOX and NO2 measured on the Ogawa filters during the two pilot studies. We observed fairly linear relationships between the time driving and pollutant mass. In this figure, filled symbols indicate samples collected during the first pilot study, and empty symbols indicate samples collected during the second pilot study. The solid colored lines show average concentrations observed in blank samplers stored in closed containers.
 
 
Figure 1.
 
After confirming the suitability of our sampling equipment and the reliability of our methods, we conducted the first field campaign in Winston-Salem from January 27 – February 21, 2013. This campaign included 46 participants (96% of goal). We deployed 184 Ogawa and 184 3M samplers (46 each of personal, indoor residential, outdoor residential, and in-vehicle), and measured the following pollutants: oxides of nitrogen (NOX), nitrogen dioxide (NO2), ozone (O3), sulfur dioxide (SO2), pentanes, isoprene, n-nonane, n-decane, n-undecane, n-dodecane, benzene, toluene, m-xylene, and o-xylene.
 
We also deployed 17 blank samples (9%) and 13 duplicate samples (9% of possible maximum, as no personal duplicates were intended to be deployed, to reduce participant burden). The samplers were submitted to University of Washington laboratories in late February and we have received the laboratory results in the past week, but the data have not yet been analyzed. Table 1 (below) shows the demographic characteristics of 1) the subgroup who participated in the first CCAR Project 5 field campaign and 2) the complete MESA Air cohort in Winston-Salem. As intended, the subgroup we recruited is fairly well representative of the Winston-Salem cohort as a whole.
 
Table 1.

 

Future Activities:

The next field campaign will be during the “non-heating” season in Winston-Salem in August 2013. This will be followed by two campaigns in Los Angeles, scheduled for February and June of 2014. We have complete IRB approval at the University of Washington and Wake Forest University for all of these activities and recently have applied for IRB approval at UCLA.
 
In addition to focusing a significant amount of effort on these field campaigns, our immediate next goals are to analyze the data collected in the first Wake Forest sampling campaign to understand the relative importance of time spent in transit to total personal exposure. This will help us determine how to generate individual exposure estimates for all MESA Air participants, for use in epidemiological analyses.


Journal Articles on this Report : 4 Displayed | Download in RIS Format

Other subproject views: All 21 publications 12 publications in selected types All 12 journal articles
Other center views: All 172 publications 76 publications in selected types All 75 journal articles
Type Citation Sub Project Document Sources
Journal Article Bergen S, Sheppard L, Sampson PD, Kim SY, Richards M, Vedal S, Kaufman JD, Szpiro AA. A national prediction model for PM2.5 component exposures and measurement error-corrected health effect inference. Environmental Health Perspectives 2013;121(9):1017-1025. R834796 (2013)
R834796 (2014)
R834796C005 (2013)
R831697 (2013)
R831697 (Final)
R833864 (2011)
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  • Journal Article Sun M, Kaufman JD, Kim S-Y, Larson TV, Gould TR, Polak JF, Budoff MJ, Diez Roux AV, Vedal S. Particulate matter components and subclinical atherosclerosis:common approaches to estimating exposure in a Multi-Ethnic Study of Atherosclerosis cross-sectional study. Environmental Health 2013;12:39. R834796 (2013)
    R834796 (2014)
    R834796 (2015)
    R834796C005 (2013)
    R834796C005 (2015)
    R834796C005 (2016)
    R831697 (2013)
    R831697 (Final)
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  • Journal Article Szpiro AA, Sheppard L, Adar SD, Kaufman JD. Estimating acute air pollution health effects from cohort study data. Biometrics 2014;70(1):164-174. R834796 (2013)
    R834796 (2014)
    R834796 (2015)
    R834796C005 (2013)
    R834796C005 (2015)
    R834796C005 (2016)
    R831697 (2013)
    R831697 (Final)
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  • Journal Article Vedal S, Kaufman JD. What does multi-pollutant air pollution research mean? American Journal of Respiratory and Critical Care Medicine 2011;183(1):4-6. R834796 (2012)
    R834796 (2013)
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    R834796C005 (2013)
    R834796C005 (2016)
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  • Supplemental Keywords:

    Cardiovascular disease, subclinical, Health, Scientific Discipline, Air, ENVIRONMENTAL MANAGEMENT, Air Quality, air toxics, Health Risk Assessment, Risk Assessments, mobile sources, 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

    Relevant Websites:

    Center for Clear Air Research Exit EPA Disclaimer

    Progress and Final Reports:

    Original Abstract
    2011 Progress Report
    2012 Progress Report
    2015 Progress Report
    2016 Progress Report


    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