Grantee Research Project Results

1999 Progress Report: Assessing Human Exposures to Particulate and Gaseous Air Pollutants

EPA Grant Number: R827353C001
Subproject: this is subproject number 001 , established and managed by the Center Director under grant R827353
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Health Effects Institute (2015 - 2020)
Center Director: Greenbaum, Daniel S.
Title: Assessing Human Exposures to Particulate and Gaseous Air Pollutants
Investigators: Koutrakis, Petros
Current Investigators: Koutrakis, Petros , Suh, Helen H. , Brown, Kathleen Ward , Sarnat, Jeremy
Institution: Harvard University
EPA Project Officer: Chung, Serena
Project Period: June 1, 1999 through May 31, 2005 (Extended to May 31, 2006)
Project Period Covered by this Report: June 1, 1999 through May 31, 2000
Project Amount: Refer to main center abstract for funding details.
RFA: Airborne Particulate Matter (PM) Centers (1999) RFA Text | Recipients Lists
Research Category: Particulate Matter , Air Quality and Air Toxics , Air

Objective:

The overall objective of this project is to improve our ability to characterize air pollutant exposures for health effects studies. This project is one of three research studies proposed under Theme I: Assessing Particle Exposures for Health Effects Studies that were based on personal, indoor, and outdoor particulate and gas concentrations that were measured as part of our previous or current exposure studies. This project was intended to address Particulate Matter Research Topics 1, 5, and 7 identified by the National Research Council (NRC)—Outdoor Measures vs. Actual Exposures for Particles, Particle Components, and Gaseous Co-Pollutants.

This project was intended to examine the ability of outdoor particulate concentrations to estimate exposures for a community. Findings from recent studies conducted by a variety of researchers have found relatively strong associations between personal PM2.5, and to a lesser degree PM10, exposures and ambient concentrations over time. Although the strength of these associations varied substantially by individual, results from one of our recent studies of individuals with chronic obstructive pulmonary disease (COPD) (Rojas-Bracho, et al., 2000) indicated that for certain individuals ambient PM2.5 concentrations are an appropriate surrogate for personal PM2.5 exposures. This observed inter-personal variability was attributed to variability in indoor PM2.5 concentrations, as the association between personal PM2.5 exposures and outdoor concentrations was strongly correlated with corresponding associations between outdoor and indoor PM2.5 concentrations. This finding suggested that indoor sources and indoor ventilation characteristics are important determinants of personal PM2.5 exposures and their relationship to outdoor levels.

Progress Summary:

We explored this issue further in our study of older adults conducted in Baltimore, MD (Sarnat, et al., 2000). Findings from this study confirmed that indoor ventilation was one of the key determinants of both personal PM2.5 exposures and their relationship to corresponding outdoor concentrations. Perhaps more significantly, findings also showed that personal-ambient associations for PM2.5 were: (1) not individual-specific, (2) strong when windows were open indoors, and (3) weak when windows were closed indoors. The influence of ventilation was attributed to its combined effect on effective penetration efficiency and indoor particulate emissions, where in indoor environments with closed windows, the effective penetration efficiency of particles from outdoor to indoor environments was lower but the accumulation of particles from indoor sources was greater. These results suggest that ambient PM2.5 concentrations are appropriate surrogates of exposures to particles of ambient origin. They further suggest that the ability of ambient PM2.5 concentrations to act as a surrogate for personal exposures may vary by region of the country or season, as ventilation characteristics may differ by both parameters. This variability in the personal exposure-ambient concentration relationship for PM2.5 may have contributed to the observed variability in particle-related health risks in epidemiological studies.

These personal-ambient associations were unique to PM2.5 and were not observed for any of the other measured co-pollutants, including O3, SO2, NO2, and PM2.5-10. Personal exposures for these co-pollutants were not significantly associated with corresponding ambient concentrations, nor were they significantly related to corresponding personal exposures to total PM2.5 or PM2.5 of ambient origin. As a result, the potential for confounding appears to be limited, despite significant correlations that were observed among ambient pollutant concentrations. These findings provide the first evidence from an exposure study that the effects observed in the PM epidemiological studies are probably not due to confounding by the measured co-pollutants. Strong correlations between the measured ambient co-pollutant concentrations and personal PM2.5 exposures, however, suggest that ambient co-pollutant concentrations may be acting as surrogates for exposures to PM2.5 or PM2.5 of ambient origin.

Future Activities:

We will continue to investigate the relationship between personal particulate exposures and corresponding ambient concentrations and the potential for confounding by gaseous pollutants in several multi-pollutant exposure studies of sensitive cohorts. These studies, which are being conducted in a variety of cities (Atlanta, GA; Boston, MA; Los Angeles, CA; and Steubenville, OH), represent a significant advance over our previous studies, because they allow us to assess concentrations of specific particulate components in addition to the more traditional PM2.5 or PM10 measurements. For each study participant, for example, we measure simultaneously the personal exposures and indoor and outdoor concentrations of PM2.5, PM10, and gaseous co-pollutants (ozone, sulfur dioxide, and nitrogen dioxide) as before. In addition, we also are measuring personal, indoor, and outdoor concentrations of important particulate constituents, sulfate (SO4^2-), nitrate (NO3-), elemental carbon (EC), organic carbon (OC), and elements. These measurements are now possible due to the recent development of our multi-pollutant sampler, which allows simultaneous measurements to be made for varying combinations of PM2.5, PM10, SO4^2-, NO3-, EC/OC, elements, O3, SO2, and NO2 using a single sampling pump (Demokritou, et al., 2000).

Journal Articles:

No journal articles submitted with this report: View all 6 publications for this subproject

Supplemental Keywords:

particulate matter, PM2.5, PM10, air pollutants, particulates, health effects, exposure, ambient particles, susceptibility, metals, public policy, biology, engineering, epidemiology, toxicology, environmental chemistry, monitoring., Health, RFA, Air, Scientific Discipline, Risk Assessments, particulate matter, Biology, Environmental Chemistry, Epidemiology, Environmental Microbiology, Molecular Biology/Genetics, Air Pollution Monitoring, indoor air, Atmospheric Sciences, Toxicology, air toxics, Environmental Monitoring, epidemelogy, respiratory disease, indoor air quality, human health, inhaled, sensitive populations, air quality, pulmonary disease, ambient monitoring, particle size, ambient air monitoring, indoor exposure, respiratory, human exposure, measurement methods, risk assessment, genetic susceptibility, chemical exposure, chronic effects, particulate exposure, cardiopulmonary responses, dosimetry, pulmonary, lung, monitoring, COPD, developmental effects, ambient particle health effects, children, particulates, exposure, PM, inhalation toxicology, air pollutants, ambient air, air pollution, cardiovascular disease, human health risk, ambient air quality, human health effects, cardiopulmonary, particle exposure, inhalation, ambient measurement methods, exposure and effects

Relevant Websites:

http://www.hsph.harvard.edu/epacenter/homeframe.htm Exit

Progress and Final Reports:

Original Abstract

Main Center Abstract and Reports:

R827353 Health Effects Institute (2015 - 2020)

Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R827353C001 Assessing Human Exposures to Particulate and Gaseous Air Pollutants
R827353C002 Quantifying Exposure Error and its Effect on Epidemiological Studies
R827353C003 St. Louis Bus, Steubenville and Atlanta Studies
R827353C004 Examining Conditions That Predispose Towards Acute Adverse Effects of Particulate Exposures
R827353C005 Assessing Life-Shortening Associated with Exposure to Particulate Matter
R827353C006 Investigating Chronic Effects of Exposure to Particulate Matter
R827353C007 Determining the Effects of Particle Characteristics on Respiratory Health of Children
R827353C008 Differentiating the Roles of Particle Size, Particle Composition, and Gaseous Co-Pollutants on Cardiac Ischemia
R827353C009 Assessing Deposition of Ambient Particles in the Lung
R827353C010 Relating Changes in Blood Viscosity, Other Clotting Parameters, Heart Rate, and Heart Rate Variability to Particulate and Criteria Gas Exposures
R827353C011 Studies of Oxidant Mechanisms
R827353C012 Modeling Relationships Between Mobile Source Particle Emissions and Population Exposures
R827353C013 Toxicological Evaluation of Realistic Emissions of Source Aerosols (TERESA) Study
R827353C014 Identifying the Physical and Chemical Properties of Particulate Matter Responsible for the Observed Adverse Health Effects
R827353C015 Research Coordination Core
R827353C016 Analytical and Facilities Core
R827353C017 Technology Development and Transfer Core

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