1999 Progress Report: Physicochemical Parameters of Combustion Generated Atmospheres as Determinants of PM Toxicity

EPA Grant Number: R827351C005
Subproject: this is subproject number 005 , established and managed by the Center Director under grant R827351
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: EPA NYU PM Center: Health Risks of PM Components
Center Director: N/A
Title: Physicochemical Parameters of Combustion Generated Atmospheres as Determinants of PM Toxicity
Investigators: Chen, Lung Chi
Institution: New York University School of Medicine
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
RFA: Airborne Particulate Matter (PM) Centers (1999) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Particulate Matter , Air

Objective:

The overall objective of this research project is to determine whether the toxicological effects associated with combustion-generated particulate matter (PM) depend on specific physicochemical characteristics of the particles. Specifically, we will: (1) determine the influence of physicochemical parameters of combustion-generated PM on the time course, dose response, and persistence of particle-induced cardiopulmonary effects; and (2) develop an animal model of cardiac ischemia induced by left coronary artery ligation.

Progress Summary:

We have developed two furnace systems that produce realistic combustion effluents with one (FeCS furnace system) consisting of a mixture of carbon, SO2, and iron, and the other (carbon organic [CO] furnace system) consisting of carbon and organic irritants. This will allow for the determination of specific components, which may be responsible for adverse health effects and assessment of whether any effects could be nonspecific (i.e., they will follow inhalation of any type of particle).

To produce Fe- and S-coated carbon particles, sucrose solutions containing varying concentrations of Fe2(SO4)3 were produced by a nebulizer and burned in the FeCS furnace system (see Figure 1). The mass median diameters of particles produced by a Collison nebulizer (before combustion) using 10 and 20 percent sucrose solutions (each containing 1,117 ppm Fe) were 0.9 μm and 1.2 μm, respectively. When a 10 percent sucrose solution containing 1,117 ppm Fe was burned in the FeCS furnace at 750 °C, ultrafine particles with a median diameter of 32 nm and a geometric standard deviation of 1.55 were produced. As shown in Figures 2a and 2b, mass concentrations decreased with increasing temperature as the sucrose particles began to burn more efficiently. Concurrently, the number concentrations increased with increasing temperature as ultrafine particles were formed. The number concentration reached a maximum at approximately 750 °C. Above 800 °C, the combustion approached completion as the number concentrations began to decrease. Because ultrafine particles have little mass, the mass concentrations approached the detection limit of the instrument at higher temperatures. In a separate experiment, number concentration as high as 1.9 x 10 7 particles/cc were achieved. Ultrafine particles also were produced in the presence of 1 ppm SO2. However, because our x-ray fluorescence analysis system was not operational, we had not confirmed the presence of Fe and S on these particles.

The Schematic Diagram of the FeCS Furnace System

Figure 1.The Schematic Diagram of the FeCS Furnace System

Mass and Number Concentration at Different Combustion Temperatures A

Figure 2a. Mass and Number Concentration at Different Combustion Temperatures

Mass and Number Concentration at Different Combustion Temperatures B

Figure 2b. Mass and Number Concentration at Different Combustion Temperatures

A schematic diagram of the CO furnace is shown in Figure 3. This furnace had been used previously to produce sulfuric acid-coated carbon particles. The carbon particles were produced by thermodecomposition of C2H2 in argon. Depending on the concentrations of C2H2 used, fine and ultrafine carbon particles up to 300 μ/m3 were produced. The system was refurbished with a new quartz tube, and it is currently used for sham exposures before it is used to produce carbon particles.

Schematic Diagram of the CO Furnace System

Figure 3. Schematic Diagram of the CO Furnace System

Effects of Particle-Associated Organic Irritants on the Cardiovascular System

Organics comprise a significant fraction of the mass of PM, but the role of these components in producing adverse biological effects has received little attention. Our objective is to examine the effects of particle-associated organic irritants on the cardiovascular system.

Dr. Nadziejko visited the laboratory of Dr. Fritz Leenen at the University of Ottawa Heart Institute to watch the procedure for installing a snare occluder around the coronary artery of a rat. The occluder is externalized to the back of the animal and can be tightened and released to cause reversible ischemia in a conscious animal. We have been successful in orally intubating rats, ventilating them mechanically, and opening and closing their chests. The next step will be to perfect the technique for inserting the snare occluder around the left coronary artery.

Hardware and software for electrocardiogram (EKG) telemetry for monitoring up to 30 rats have been purchased and are in use. We currently have 14 young rats with internal EKG transmitters. We have an additional group of 14 aged rats (14 months old) that will have transmitters implanted in the next few weeks so that young and old rats can be studied concurrently. The experimental protocol has been modified to allow for repeated exposure of the same rats to different atmospheres. Baseline monitoring is conducted for 48 hours before every experiment, during each 3-hour exposure, and for 48 hours after exposure to verify that EKG parameters return to baseline. Exposures are separated by at least 1 week. Every experiment is conducted in duplicate with a cross-over design.

The effects of restraint on heart rate have been examined in a series of experiments comparing restrained animals to animals maintained in their cages. These experiments showed that the size of the holder was a much more important factor in preventing heart rate increases than gradual adaptation to the restraint. Two experiments have been conducted in which one group of rats was exposed to filtered air, and the other group was exposed to filtered air from the furnace (as a sham control to verify that there are no artifactual effects on EKG parameters). The results of these experiments are being analyzed.

Improved procedures for managing and analyzing EKG data (including quality assurance) have been developed. EKG monitoring generates large numbers of data files. We have set up procedures using the Sun workstation, SAS, and Splus to efficiently transfer these files into databases for statistical analysis and graphical analysis. We have developed methods for analysis of heart rate variability and blood pressure variability, including a program to perform spectral analysis on beat-to-beat interval data. We currently are collecting data for heart rate variability analysis with every experiment, but have not yet analyzed the data.

Future Activities:

We will produce a mixture of carbon, sulfur dioxide, and metal (Fe or Cu). We will update the two furnace systems and the electronics for temperature regulation. We will generate and burn in sucrose solutions containing varying concentrations of Fe(NO3)3 (or Cu[NO3]2) to produce Fe (or Cu), and sulfur-coated C particles. We will use x-ray fluorescence spectroscopy (XRF) to measure the concentrations of Fe, Cu, and S in these particles. We will expose Sprague Dawley rats to furnace gas, or to 450 µg/m 3 of these particles in furnace gas, for 3 hours and then lavage their lungs 24 hours post-exposure. A lead oxide diffusion denuder will be used to remove SO2 from the exposure atmospheres.

Journal Articles:

No journal articles submitted with this report: View all 5 publications for this subproject

Supplemental Keywords:

thoracic particles, particulate matter, PM, PM10, fine particles, PM2.5, ultrafine particles, PM0.1, lung dosimetry models, human exposure models, pulmonary responses, cardiovascular responses, immunological responses, criteria air pollutants, concentrated ambient aerosols, air, health, waste, biochemistry, biology, chemical engineering, chemistry, children’s health, civil engineering, environmental engineering, environmental chemistry, physics, analytical chemistry, epidemiology, health risk assessment, immunology, incineration, combustion, combustion contaminants, combustion emissions, air toxics, tropospheric ozone, aerosol, air pollutants, air pollution, airborne pollutants, airway disease, airway inflammation, airway variability, allergen, ambient air, ambient air quality, assessment of exposure, asthma, asthma morbidity, atmospheric monitoring, biological markers, childhood respiratory disease, children, compliance monitoring, dosimetry, exposure, exposure and effects, health effects, heart rate variability, human exposure, human health, human health effects, lead, lung, mercury, morbidity, pulmonary, pulmonary disease, respiratory, toxicology, physicochemical, cardiopulmonary, metal, furnace, rats, animal, sulfur dioxide, acute cardiovascular effects, aerosol composition, air toxics, airborne particulate matter, ambient air monitoring, atmospheric aerosol particles, atmospheric particles, atmospheric particulate matter, chemical characteristics, combustion byproducts, dose response, environmental risks, exposure assessment, heavy metals, human health risk, particulates, mass median diameters, x-ray fluorescence, XRF,, RFA, Health, PHYSICAL ASPECTS, Scientific Discipline, Air, ENVIRONMENTAL MANAGEMENT, Waste, INDUSTRY, POLLUTANTS/TOXICS, particulate matter, Environmental Chemistry, Health Risk Assessment, Chemicals, Risk Assessments, Physical Processes, Environmental Monitoring, Industrial Processes, Incineration/Combustion, Risk Assessment, ambient air quality, atmospheric particulate matter, particulates, combustion byproducts, air toxics, atmospheric particles, chemical characteristics, toxicology, ambient air monitoring, acute cardiovascular effects, airborne particulate matter, environmental risks, exposure, combustion emissions, dose response, air pollution, Sulfur dioxide, aerosol composition, atmospheric aerosol particles, human exposure, combustion, PM, exposure assessment, human health risk

Relevant Websites:

http://www.med.nyu.edu/environmental/centers/epa/ Exit

Progress and Final Reports:

Original Abstract
  • 2000 Progress Report
  • 2001 Progress Report
  • 2002 Progress Report
  • 2003
  • 2004
  • Final Report

  • Main Center Abstract and Reports:

    R827351    EPA NYU PM Center: Health Risks of PM Components

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R827351C001 Exposure Characterization Error
    R827351C002 X-ray CT-based Assessment of Variations in Human Airway Geometry: Implications for Evaluation of Particle Deposition and Dose to Different Populations
    R827351C003 Asthma Susceptibility to PM2.5
    R827351C004 Health Effects of Ambient Air PM in Controlled Human Exposures
    R827351C005 Physicochemical Parameters of Combustion Generated Atmospheres as Determinants of PM Toxicity
    R827351C006 Effects of Particle-Associated Irritants on the Cardiovascular System
    R827351C007 Role of PM-Associated Transition Metals in Exacerbating Infectious Pneumoniae in Exposed Rats
    R827351C008 Immunomodulation by PM: Role of Metal Composition and Pulmonary Phagocyte Iron Status
    R827351C009 Health Risks of Particulate Matter Components: Center Service Core
    R827351C010 Lung Hypoxia as Potential Mechanisms for PM-Induced Health Effects
    R827351C011 Urban PM2.5 Surface Chemistry and Interactions with Bronchoalveolar Lavage Fluid (BALF)
    R827351C012 Subchronic PM2.5 Exposure Study at the NYU PM Center
    R827351C013 Long Term Health Effects of Concentrated Ambient PM2.5
    R827351C014 PM Components and NYC Respiratory and Cardiovascular Morbidity
    R827351C015 Development of a Real-Time Monitoring System for Acidity and Soluble Components in Airborne Particulate Matter
    R827351C016 Automated Real-Time Ambient Fine PM Monitoring System