2002 Progress Report: Measurement of the “Effective” Surface Area of Ultrafine and Accumulation Mode PM (Pilot Project)

EPA Grant Number: R827352C003
Subproject: this is subproject number 003 , established and managed by the Center Director under grant R827352
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: Southern California Particle Center and Supersite
Center Director: Froines, John R.
Title: Measurement of the “Effective” Surface Area of Ultrafine and Accumulation Mode PM (Pilot Project)
Investigators: Friedlander, Sheldon , Sioutas, Constantinos
Institution: University of California - Los Angeles , Michigan State University , University of California - Irvine , University of Southern California
Current Institution: University of California - Los Angeles , University of Southern California
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, 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 focus on the central hypothesis of the Southern California Particle Center and Supersite, which is that organic constituents associated with particulate matter (PM)—including quinones, other organic compounds (polycyclic aromatic hydrocarbons [PAHs], nitro-PAHs, and aldehydes/ketones), and metals—are capable of generating reactive oxygen species and acting as electrophilic agents. They have a central role in allergic airway disease such as asthma and cardiovascular effects through their ability to generate oxidative stress, inflammation, and immunomodulating effects in the lungs and airways.

This research project will systematically evaluate the effective density and surface area of ambient ultrafine PM. The methodology will allow for a direct comparison of "mobility" diameter—a function of particle surface area and shape—and "aerodynamic" diameter—a function of particle inertia only. The specific objectives of this research project are to: (1) study the variation in aerosol morphological properties around the Los Angeles Airshed, including surface area, fractal dimension, number of primary particles per aggregate, etc; (2) compare our results with measurements made with new aerosol instruments; and (3) compare size distributions measured with respect to aerodynamic and electrical mobility diameters using a novel method under development by our group.

Progress Summary:

The results of preliminary measurements made last summer as part of the current study were inconsistent with the earlier studies conducted by our group. We feel that this was because of the use of a new impactor; in addition, there was leakage in repeat measurements made with the original impactor. Adjustments have been made in the experimental system to correct these problems, and new measurements have been initiated. Currently, the samples are being analyzed by transmission electron microscopy to determine the range of aerodynamic diameters associated with a selected electrical mobility diameter. The results of these studies will have the following applications:

(1) There is evidence that aggregate morphology influences injury to lung cells.

(2) Lung deposition of the ultrafine atmospheric aerosol will depend on particle morphology.

(3) The residence times of atmospheric aggregates will depend on their morphology.

Figure 1. Transmission Electron Photomicrographs of Fractal-Like Aggregates With Aerodynamic Diameters 75-120 nm

Figure 1. Transmission Electron Photomicrographs of Fractal-Like Aggregates With Aerodynamic Diameters 75-120 nm

Figure 2. Transmission Electron Photomicrograph of Fractal-Like Aggregates With Aerodynamic Diameters 75-120 nm (From Xiong and Friedlander [2001])

Figure 2. Transmission Electron Photomicrograph of Fractal-Like Aggregates With Aerodynamic Diameters 75-120 nm (From Xiong and Friedlander [2001])

Future Activities:

We will complete the study of the comparison of the aerodynamic and electrical mobility diameters for atmospheric aerosol. The distribution of aerodynamic diameters associated with a narrow range of electrical mobility diameters will be determined quantitatively with the characterization of particle morphology. We will characterize the surface area of ultrafine atmospheric aerosol with respect to spatial variation in the Los Angeles Airshed with Professor Sioutas. Atmospheric aerosol will be collected at the Supersite sampling locations to characterize the exposure levels of PM surface area in the Los Angeles Basin. A surface area distribution will be constructed and compared to surface area distributions calculated using scanning mobility particle sizer measurements, which assume spherical morphology. With the presence of atmospheric aggregates, it is expected that the assumption of spherical morphology leads to an underestimation of the ultrafine aerosol surface area. During the second half of this research project, we will collaborate with Dane Westerdahl of the Air Resources Board in sampling aerosol on Los Angeles freeways. We will characterize particle morphology on freeways with heavy diesel traffic and compare our measurements of aggregate surface area and fractal dimension with the measurement of the electrical aerosol detector (TSI Model 3070).

Journal Articles:

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

Supplemental Keywords:

Particulate matter, quinones, PAHs, aldehydes, ketones, metals, allergic airway disease, human health risk, asthma, cardiovascular effects, oxidative stress, ultrafine particulate matter, aerosol morphological properties, atmospheric aerosol, environmental monitoring, Los Angeles, CA,, RFA, Health, Scientific Discipline, Air, HUMAN HEALTH, particulate matter, Environmental Chemistry, Air Pollutants, Risk Assessments, Biochemistry, Health Effects, Atmospheric Sciences, particulates, ambient aerosol, asthma, morphometric analyses, toxicology, quinones, human health effects, airway disease, allergic airway disease, ambient measurement methods, air pollution, PAH, particulate exposure, human exposure, toxicity, aerosol composition, breath samples, allergens, particle concentrator, airborne urban contaminants, human health risk, genetic susceptibility, aerosols, atmospheric chemistry, particle transport

Relevant Websites:

http://www.scpcs.ucla.edu/ exit EPA

Progress and Final Reports:

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

  • Main Center Abstract and Reports:

    R827352    Southern California Particle Center and Supersite

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R827352C001 The Chemical Toxicology of Particulate Matter
    R827352C002 Pro-inflammatory and the Pro-oxidative Effects of Diesel Exhaust Particulate in Vivo and in Vitro
    R827352C003 Measurement of the “Effective” Surface Area of Ultrafine and Accumulation Mode PM (Pilot Project)
    R827352C004 Effect of Exposure to Freeways with Heavy Diesel Traffic and Gasoline Traffic on Asthma Mouse Model
    R827352C005 Effects of Exposure to Fine and Ultrafine Concentrated Ambient Particles near a Heavily Trafficked Freeway in Geriatric Rats (Pilot Project)
    R827352C006 Relationship Between Ultrafine Particle Size Distribution and Distance From Highways
    R827352C007 Exposure to Vehicular Pollutants and Respiratory Health
    R827352C008 Traffic Density and Human Reproductive Health
    R827352C009 The Role of Quinones, Aldehydes, Polycyclic Aromatic Hydrocarbons, and other Atmospheric Transformation Products on Chronic Health Effects in Children
    R827352C010 Novel Method for Measurement of Acrolein in Aerosols
    R827352C011 Off-Line Sampling of Exhaled Nitric Oxide in Respiratory Health Surveys
    R827352C012 Controlled Human Exposure Studies with Concentrated PM
    R827352C013 Particle Size Distributions of Polycyclic Aromatic Hydrocarbons in the LAB
    R827352C014 Physical and Chemical Characteristics of PM in the LAB (Source Receptor Study)
    R827352C015 Exposure Assessment and Airshed Modeling Applications in Support of SCPC and CHS Projects
    R827352C016 Particle Dosimetry
    R827352C017 Conduct Research and Monitoring That Contributes to a Better Understanding of the Measurement, Sources, Size Distribution, Chemical Composition, Physical State, Spatial and Temporal Variability, and Health Effects of Suspended PM in the Los Angeles Basin (LAB)