2002 Progress Report: Toxicology Project -- Controlled Exposure Facility

EPA Grant Number: R827355C006
Subproject: this is subproject number 006 , established and managed by the Center Director under grant R827355
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: Airborne PM - Northwest Research Center for Particulate Air Pollution and Health
Center Director: Koenig, Jane Q.
Title: Toxicology Project -- Controlled Exposure Facility
Investigators: Kaufman, Joel D. , Covert, David S. , Larson, Timothy V. , Sullivan, Jeff , Trenga, Carol , Yost, Michael
Current Investigators: Kaufman, Joel D. , Curtiss, Heidi M , Gemar, Kjersti A , Gould, Timothy , Jarvis, SS , Larson, Timothy V. , Sands, FN , Shepherd, Kristine , Stewart, James A , Sullivan, Jeff , Trenga, Carol
Institution: University of Washington
EPA Project Officer: Chung, Serena
Project Period: June 1, 1999 through May 31, 2004 (Extended to May 31, 2006)
Project Period Covered by this Report: June 1, 2001 through May 31, 2002
RFA: Airborne Particulate Matter (PM) Centers (1999) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Particulate Matter , Air

Objective:

The objective of this research project is to construct a controlled exposure facility at the University of Washington that will have the capability to expose human subjects to combustion-derived particles and complex air pollution mixtures such as diesel exhaust.

Progress Summary:

During the last year, the major modifications to the facility have been completed. We now are able to generate fresh diluted diesel exhaust, rich in ultrafine particles, in the chamber for both human and animal exposure studies. Hypotheses have been developed around both cardiovascular and asthmatic outcomes. Pilot studies are planned and will begin soon. Currently, equipment has been obtained, Institutional Review Board approval is in hand, and exposure characterization studies are underway. Following comments from the External Science Advisory Committee, modifications to the diesel exposure chamber were completed to allay concerns about sorption and desorption of volatile organic compounds (VOCs) to and from the chamber and system materials.

Northlake Laboratory Facility for Combustion-Derived Particulate Exposures

The evolving experimental and epidemiological evidence that ambient levels of fine particulate matter (PM) are associated with significant cardiovascular and respiratory health effects raises many questions. PM from combustion sources is likely of special concern, and diesel exhaust has been especially implicated.

This pilot project will convert the existing Northlake ventilation laboratory into a facility for controlled exposure to combustion-derived PM. This new laboratory will be an important resource for investigations into the health effects of exposures to combustion products at low-level occupational or near-ambient levels. The initial exposure system being developed will generate an environment mimicking ambient PM from heavy-duty diesel engines, such as those found in trucks, school buses, tractors, electric generators, and construction equipment.

Initial planned investigations will include a full characterization of the exposures in the chamber, pilot studies on respiratory effects in asthmatic subjects, studies on cardiovascular effects in healthy subjects, and studies on the symptoms associated with these exposures. (A separate room of the facility is available for animal exposures in toxicology experiments.) The opportunity to carefully study biomarkers of exposure and effect also is an advantage of this chamber.

Exposures occur within an existing, well-characterized 100-m3 exposure chamber. Previous measurement and tracer studies indicate the chamber can produce approximately ideal plug flow under suitable inlet temperature conditions. All subject exposures and exposure characterization occur in a 13.8 m3 central breathing and sampling zone. The air entering the room is conditioned to 18°C and 60 percent relative humidity.

Diesel exhaust PM will be derived from a current model turbocharged direct-injection 5.9-liter Cummins B-series engine (6BT5.9G6, Cummins, Inc., Columbus, IN) in a 100 kW generator set located outside the laboratory. This engine is comparable to that used in heavy-duty road applications such as delivery trucks and school buses. Fuel is #2 undyed on-highway fuel from a commercial source that will remain stable throughout the experiments. Load is maintained at 75 percent of rated capacity, using a load-adjusting load bank (Simplex, Springfield, IL) throughout the experiments. Emissions from this contemporary engine operating at load provides substantial information of interest in studying the health effects of diesel exhaust particulate derived from contemporary engines in heavy-duty trucks and nonroad diesel applications.

Emissions Dilution

Recent studies summarized by Kittelson and colleagues have shown that the number and size distribution of particles with diameters less than 50 nm are highly dependent on the rate and temperature of dilution. Our dilution system design is directly analogous to that used in the University of Minnesota laboratories. This design has a fast primary dilution of 15:1, and a subsequent tunnel residence time of 2 seconds. The secondary dilution, assisted by turbulence in a 1,000-cfm tunnel, results in final breathing zone concentrations between 15 and 200 µg/m3 PM2.5 diesel exhaust particles, which we calibrate to experimental concentrations using a flow splitter after the primary dilution. All dilution air for the system is passed through high efficiency particulate air (HEPA) filters, permitting a filtered air control exposure option with very low particulate levels.

The facility will represent an important resource, and its development and support represents an important initiative for the Center.

Future Activities:

During the next year, we anticipate completing the initial exposure characterization and pilot studies in healthy subjects. The facility also serves as the platform for a grant to be funded by the U.S. Environmental Protection Agency entitled: Effect of Diesel Exhaust Particulate Exposures on Endothelial Function in Humans: The Role of Oxidative Stress (R830954). Other studies also are being planned that will take advantage of this facility.

Journal Articles:

No journal articles submitted with this report: View all 4 publications for this subproject

Supplemental Keywords:

air pollution, air pollutants, particulate matter, PM, diesel, diesel exhaust, diesel exhaust particles, DEP, ultrafine particles, fine particles, PM2.5, cardiovascular health effects, health effects, respiratory health effects, ambient levels, combustion products, diesel engines, occupational levels, toxicology, toxicity, exposure, controlled exposure facility, asthma, volatile organic compounds, VOCs, human exposure, animal exposure, susceptible populations., RFA, Health, Scientific Discipline, PHYSICAL ASPECTS, Air, ENVIRONMENTAL MANAGEMENT, particulate matter, Toxicology, air toxics, Environmental Chemistry, Health Risk Assessment, Air Pollutants, Epidemiology, Air Pollution Effects, Risk Assessments, Biochemistry, Physical Processes, Atmospheric Sciences, Risk Assessment, health effects, ambient aerosol, particulates, ambient air quality, cardiopulmonary responses, human health effects, exposure and effects, animal model, exposure, air pollution, particle exposure, diesel exhaust, atmospheric aerosols, ambient particle health effects, inhalation, human exposure, PM, particle transport, cardiovascular disease, human health risk, aerosols, atmospheric chemistry

Relevant Websites:

http://depts.washington.edu/pmcenter/ Exit

Progress and Final Reports:

Original Abstract
  • 1999
  • 2000
  • 2001 Progress Report
  • 2003
  • 2004
  • Final Report

  • Main Center Abstract and Reports:

    R827355    Airborne PM - Northwest Research Center for Particulate Air Pollution and Health

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R827355C001 Epidemiologic Study of Particulate Matter and Cardiopulmonary Mortality
    R827355C002 Health Effects
    R827355C003 Personal PM Exposure Assessment
    R827355C004 Characterization of Fine Particulate Matter
    R827355C005 Mechanisms of Toxicity of Particulate Matter Using Transgenic Mouse Strains
    R827355C006 Toxicology Project -- Controlled Exposure Facility
    R827355C007 Health Effects Research Core
    R827355C008 Exposure Core
    R827355C009 Statistics and Data Core
    R827355C010 Biomarker Core
    R827355C011 Oxidation Stress Makers