2004 Progress Report: Characterization of the Chemical Composition of Atmospheric Ultrafine Particles

EPA Grant Number: R827354C001
Subproject: this is subproject number 001 , established and managed by the Center Director under grant R827354
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: Airborne PM - Rochester PM Center
Center Director: Oberd√∂rster, G√ľnter
Title: Characterization of the Chemical Composition of Atmospheric Ultrafine Particles
Investigators: Hopke, Philip K. , Prather, Kimberly A. , Dillner, Ann , Cass, Glen
Current Investigators: Cass, Glen , Prather, Kimberly A. , Hopke, Philip K. , Dillner, Ann
Institution: Clarkson University , Arizona State University - Main Campus , Georgia Institute of Technology , University of California - Riverside
Current Institution: Georgia Institute of Technology , Arizona State University - Main Campus , Clarkson University , University of California - Riverside
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, 2004 through May 31, 2005
RFA: Airborne Particulate Matter (PM) Centers (1999) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Particulate Matter , Air


The objective of this research project is to provide improved understanding of the chemical and physical nature of the ultrafine ambient aerosol. There is relatively little data available that provides distinct information on particles in the size range less than 100 nm. Because of the relatively small amount of particle mass in this size range, sampling and chemical analysis is difficult. Such physical and chemical data, however, provide critical information to the epidemiological and toxicological studies to help guide their investigations of the relationships of the ultrafine particles and adverse health effects. Initially, the focus of this core study has been on the development of effective methods to sample and analyze ultrafine particles. Now, these methods are being applied to characterize the ultrafine aerosol in a number of locations across the country to assess the variations that exist in the nature of the ultrafine particles.

Progress Summary:

Years 1-5

In the early stage of this project, the Cass/Dillner group collected ultrafine particle samples in field experiments in a south central U.S. city (Houston, TX) (Dillner, et al., 2005) and in a west coast city (Riverside, CA), using automated equipment that measures ultrafine aerosol size distributions. The Prather group completed the development of an improved aerosol time of flight mass spectrometry instrument to measure the chemical composition of single atmospheric particles smaller than 100 nm in particle diameter. An ultrafine particle aerosol time of flight mass spectrometry instrument has been constructed incorporating an aerodynamic lens system, which allows transmission of ultrafine particles into the instrument. An effective method for detecting ultrafine particles in the systems has been developed and applied to study the aerosol in Rochester and Atlanta. The Hopke group has developed an assay to determine the quantity of reactive oxidative species associated with airborne particulate matter and have used it in studies in Rubidoux, California, during the summer and in New York City, New York, in the winter. During Year 5 of the project, an intensive effort was made to examine the behavior of ambient aerosol concentrators to better understand the properties of the particles that they provide for exposures to people or animal models.

Year 6 Activities

Much of the activities in Year 6 involved completion of the analysis of the data collected during the prior years of the project. In particular, our collaboration with the winter intensive study of the New York City Supersite has resulted in several joint publications (Zhou, et al., 2005; Venkatachari, et al., 2005b,c,d). Thus, a number of publications have been written, submitted, accepted, and published.

Characterization of Concentrated Ambient Particles (CAPs). Comprehensive data analyses have been completed on the datasets collected in Rochester, New York (2002), Boston, Massachusetts (2003), Tuxedo Park, New York (2003), and Chapel Hill, North Carolina (2003). Results have been published or accepted for publication (Moffet, et al., 2004; Su, et al., 2005a,b). The study of the coarse particle concentrator showed it produced little, if any, change in the nature of the particles. In the case of the ultrafine particle concentrator, experimental results of the single particle mixing state suggest that particles undergo repartitioning of chemical species during the enrichment processes at supersaturation ratios of 3.0 and lower. In comparing the relative fractions of particles in concentrated versus nonconcentrated ambient air, a significant decrease was observed in nominally fresh ultrafine elemental carbon (EC) particles relative to EC particles coated with organic carbon (OC) after undergoing the concentration process. Concentrated ultrafine particles showed a 30 percent increase in OC on EC particles for the same nominal aerodynamic size. An increase in the number fraction of aromatic- and polycyclic aromatic hydrocarbon-containing particles also was observed in both the ultrafine and the fine modes. Such changes are attributed to gas-to-particle partitioning of organic components (e.g., water-soluble organic compounds) onto pre-existing ultrafine and fine particles during the particle enrichment process, which involves supersaturation, condensation, desolvation, and evaporation for particle growth and size restoration.

Particle-Bound Reactive Oxidative Species. Reactive oxygen species (ROS), a term used to collectively describe oxygen-containing species with strong oxidizing ability, include molecules like hydrogen peroxide (H2O2), ions like the hypochlorite ion (OCl‾) and superoxide anion ( O2‾), and radicals like the hydroxyl (OH) radical and the superoxide anion (O2‾). One of the hypotheses for the adverse health effects of airborne particulate matter is the effects of ROS, formed by metals acting as catalysts for Fenton reactions, at concentrations that cause inflammation and lead to systemic dysfunctions (Stohs and Bagchi,1995). ROS species, however, are present in the atmosphere associated with respirable particles to which we are exposed. It is the purpose of our studies to determine the concentration of these reactive oxygen species in the background atmosphere, carried by atmospheric particles. This work is described by Venkatachari, et al. (2005a,d).

In addition, a reactive oxygen species particle generator has been developed and tested. We have nebulized solutions of α-pinene and reacted it with O3 in a tube reactor. The solvent and the ozone are then removed with an activated carbon diffusion denuder. Currently, we are testing the stability of the generator and once we are confident in its reproducibility, it will be transported to Rochester for use in animal exposure studies.

Source Apportionment and Health Effects. A major effort has been made during this year to complete the manuscripts derived from the Workshop on Source Apportionment and PM Health Effects that was organized by the PM and Health Centers in May 2003. A summary paper has been accepted by Environmental Health Perspectives. The details of the results have been described in a series of three papers submitted to the International Journal of Exposure Analysis and Environmental Epidemiology. The first paper presents a summary of the source apportionment results among the various workshop participants and it has been accepted for publication (Hopke, et al., 2005). The two papers on health effects modeling in Washington, DC (Ito, et al., 2005) and Phoenix, AZ (Mar, et al., 2005) are being revised in accordance with the reviewers comments and will be resubmitted shortly.

Future Activities:

The investigators did not report any future activities.

Journal Articles:

No journal articles submitted with this report: View all 30 publications for this subproject

Supplemental Keywords:

pollution prevention, urban air pollution, atmosphere, metals, air, health, waste, atmospheric sciences, biochemistry, children’s health, environmental chemistry, epidemiology, genetics, virology, molecular biology, health risk assessment, risk assessments, incineration, combustion, combustion engines, air toxics, tropospheric ozone, PM2.5, particulates, ultrafine particles, particulate matter, particle exposure, particle size, aerosol, aerosols, ambient air, ambient air monitoring, ambient air quality, animal model, atmospheric, cardiopulmonary, cardiopulmonary responses, cardiovascular disease, cardiovascular vulnerability, coronary artery disease, cytokine production, fine particles, human exposure, human health, human health effects, environmental health effects, inhalation toxicology, lead, lung, lung inflammation, metals, morbidity, mortality, pathophysiological mechanisms, pulmonary, pulmonary disease, stratospheric ozone, sensitive populations, susceptible populations,, RFA, Health, Scientific Discipline, Air, Geographic Area, particulate matter, Environmental Chemistry, Health Risk Assessment, Epidemiology, State, Risk Assessments, Biochemistry, ambient air quality, particle size, particulates, sensitive populations, cardiopulmonary responses, chemical characteristics, fine particles, human health effects, morbidity, ambient air monitoring, pulmonary disease, susceptible populations, epidemelogy, particle exposure, environmental health effects, nano differential mobility analyzer, human exposure, chemical kinetics, particulate exposure, Texas (TX), PM, mortality, urban environment, aerosols, chemical speciation sampling, human health risk

Relevant Websites:

http://www2.envmed.rochester.edu/envmed/PMC/ Exit

Progress and Final Reports:

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

  • Main Center Abstract and Reports:

    R827354    Airborne PM - Rochester PM Center

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R827354C001 Characterization of the Chemical Composition of Atmospheric Ultrafine Particles
    R827354C002 Inflammatory Responses and Cardiovascular Risk Factors in Susceptible Populations
    R827354C003 Clinical Studies of Ultrafine Particle Exposure in Susceptible Human Subjects
    R827354C004 Animal Models: Dosimetry, and Pulmonary and Cardiovascular Events
    R827354C005 Ultrafine Particle Cell Interactions: Molecular Mechanisms Leading to Altered Gene Expression
    R827354C006 Development of an Electrodynamic Quadrupole Aerosol Concentrator
    R827354C007 Kinetics of Clearance and Relocation of Insoluble Ultrafine Iridium Particles From the Rat Lung Epithelium to Extrapulmonary Organs and Tissues (Pilot Project)
    R827354C008 Ultrafine Oil Aerosol Generation for Inhalation Studies