2004 Progress Report: Toxicological Evaluation of Realistic Emissions of Source Aerosols (TERESA) Study

EPA Grant Number: R827353C013
Subproject: this is subproject number 013 , 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: EPA Harvard Center for Ambient Particle Health Effects
Center Director: Koutrakis, Petros
Title: Toxicological Evaluation of Realistic Emissions of Source Aerosols (TERESA) Study
Investigators: Koutrakis, Petros
Current Investigators: Koutrakis, Petros , Lawrence, Joy , Ruiz, Pablo , Wolfson, Jack M.
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, 2003 through May 31, 2004
RFA: Airborne Particulate Matter (PM) Centers (1999) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Particulate Matter , Air

Objective:

Sources such as coal-fired power plants may produce only small quantities of primary particulate matter (PM), and most of the concern over the health impacts of power plant emissions focuses on the secondary particles formed via atmospheric oxidation of emitted SO2. The effects of secondary particles formed from vehicular emissions are also of considerable concern. However, toxicological studies of these secondary particles are difficult to carry out. The TERESA (Toxicological Evaluation of Realistic Emissions of Source Aerosols) study involves the use of mobile laboratories at power plants or sources of vehicular emissions to age these emissions, followed by animal exposures. Development of methods to carry out these studies was supported by the EPA PM Center at HSPH in conjunction with the Electric Power Research Institute and the US Department of Energy. Several power plants were included in the project to allow assessment of different coals and pollution control configurations. The primary goal of TERESA is to evaluate the comparative toxicity of secondary particles derived from coal-fired power plant emissions and vehicular sources.

Progress Summary:

Primary emissions were drawn from the power plant stack into a mobile laboratory, where several atmospheric scenarios were simulated (primary particles only, secondary particles, secondary particles + secondary organic aerosol, and secondary particles + ammonia + secondary organic aerosol). Male Sprague-Dawley rats were exposed to these atmospheric mixtures for 6 hours. Control animals were exposed to filtered air. Pulmonary function and breathing pattern data were collected during exposure, and bronchoalveolar lavage cells and fluid and blood were collected post-exposure for cytological and biochemical analyses (Rohr, et al., 2005; Godleski, et al., 2005).

PM2.5 concentrations ranged from 200-450 μg/m3 in all of the secondary particle scenarios. At the first plant studied, where primary particle emissions were very low, no differences in breathing pattern or pulmonary function, in BAL, or in blood parameters w ere observed between control and exposed animals. At the second plant where primary particle emissions were 3 times higher, but still quite low, significant differences were noted for several parameters. Significant changes in breathing pattern toward a rapid shallow breathing pattern were observed in both the secondary particles and the secondary particles + organic aerosol scenarios.

For each exposure scenario, statistical modeling was used to assess the size and strength of association between exposure and each respiratory outcome. Additive mixed models were applied to 10-minute averaged data collected from all exposed and Sham animals exposed during that scenario. A form of repeated measures model for longitudinal data, additive mixed models represent an extension of linear regression models that allows one to (1) estimate potentially non-linear effects of independent variables, and (2) include random effects as independent variables in order to account for clustering of observations that results from repeated measurements being taken on the same animal during the exposure period. For each outcome, additive mixed models were fit using as independent variables (1) a general nonlinear mean trend for sham animals over the exposure period ; (2) an exposure indicator, which implies a constant shift in the mean trend due to test exposure ; and (3) random animal effects reflecting animal-to-animal heterogeneity that results in correlation among 10-minute averages taken on the same animal over time. All models were fit using the gamma function in the R software (R Development Core Team [2004]).

Finally, a more general model that relaxed the assumption of a constant shift due to test exposure was also fit to the data. This model specified distinct mean trends over the exposure period for the SHAM and test animals, again including random animal effects to account for the repeated measurements taken on each animal. The difference between these estimated trends represents the time-varying effect of the test exposure over the exposure period.

Table 1 describes the directional trends and the level of significance of the changing trend.

Table 1. Directional Trends and Levels of Significance for Different Scenarios

Scenario

Respir Rate

Tidal Volume

Time Inspiration

Time Expiration

PenH

Sec unneut organics #1

↑ ns

↓ p = 0.003

NC…..ns

NC     ns

↓ ns

Sec unneut organics #2

↑ ns

NC…..ns

NC…..ns

NC…..ns

↓ p = 0.001

Sec unneut

↑ p = 0.06

↓ p = 0.04

↓ p = 0.02

↓ p = 0.06

↓ p = 0.01

Sec unneut MI model

↑p = 0.024

NC…..ns

NC…..ns

↓ p = 0.005

↑ p = 0.03

Sec neut organics

↓ ns

↓ p = 0.002

NC…..ns

NC…..ns

↓ p = 0.001

Primary particles

↓ ns

↓ p = 0.001

NC…..ns

NC…..ns

↓ p = 0.003

Results from the first two TERESA plants, under several different simulated atmospheric scenarios, indicate different toxicological effects with exposure to secondary particles derived from coal combustion. Definition of the basis of these differences is in progress with detailed comparative analyses of the exposure component concentrations, the type of coal burned, and other exposure variables. Studies of vehicular emissions have been planned, and arrangements are in progress for these studies to be part of our new EPA Center. Meanwhile, analysis continues on the electrocardiographic analyses of animals exposed using the MI model.

Journal Articles:

No journal articles submitted with this report: View all 1 publications for this subproject

Supplemental Keywords:

exposure, health effects, susceptibility, metals, public policy, biology, engineering, epidemiology, toxicology, environmental chemistry, monitoring, air pollutants, air pollution, air quality, ambient air, ambient air monitoring, ambient air quality, ambient measurement methods, ambient monitoring, ambient particle health effects, ambient particles, animal inhalation study, assessment of exposure, biological mechanism, biological response, cardiopulmonary, cardiopulmonary response, cardiovascular disease, chemical exposure, children, developmental effects, dosimetry, environmental health hazard, exposure and effects, genetic susceptibility, health risks, human exposure, human health, human health effects, human health risk, human susceptibility, indoor air quality, indoor exposure, inhalation, inhalation toxicology, inhaled particles, lead, measurement methods, particle exposure, particulate exposure, particulates, pulmonary, pulmonary disease, respiratory, respiratory disease, risk assessment, sensitive populations, stratospheric ozone,, RFA, Health, Scientific Discipline, Air, Air Pollution Monitoring, particulate matter, Toxicology, air toxics, Environmental Chemistry, Air Pollution Effects, Risk Assessments, Environmental Monitoring, Children's Health, indoor air, Molecular Biology/Genetics, Biology, Environmental Engineering, particulates, health effects, microbiology, ambient air quality, chemical exposure, monitoring, risk assessment, sensitive populations, cardiopulmonary responses, epidemiology, human health effects, ambient air monitoring, indoor exposure, air pollutants, exposure and effects, ambient air, biological response, ambient measurement methods, pulmonary disease, developmental effects, respiratory disease, lead, air pollution, children, Human Health Risk Assessment, particle exposure, biological mechanism , ambient monitoring, mobile sources, inhalation, pulmonary, assessment of exposure, susceptibility, particulate exposure, ambient particle health effects, human exposure, environmental health hazard, epidemeology, inhalation toxicology, tropospheric ozone, PM, indoor air quality, cardiopulmonary, human health, modeling studies, air quality, respiratory, dosimetry, animal inhalation study, cardiovascular disease, genetic susceptibility, human health risk

Progress and Final Reports:

Original Abstract
  • 1999
  • 2000
  • 2001
  • 2002
  • 2003
  • Final Report

  • Main Center Abstract and Reports:

    R827353    EPA Harvard Center for Ambient Particle Health Effects

    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