2001 Progress Report: Relationship Between Ultrafine Particle Size Distribution and Distance From Highways

EPA Grant Number: R827352C006
Subproject: this is subproject number 006 , 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: Relationship Between Ultrafine Particle Size Distribution and Distance From Highways
Investigators: Hinds, William C. , Sioutas, Constantinos , Zhu, Yifang
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, 2000 through May 31, 2001
RFA: Airborne Particulate Matter (PM) Centers (1999) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Particulate Matter , Air


This project is one of four specific studies that focus on emission sources and related adverse health effects. The study hypotheses are that:

  • Mobile source emissions will exacerbate airway inflammation and allergic airway disease and produce cardiopulmonary effects.
  • The magnitude of allergic airway disease and cardiovascular effects from mobile sources are a function of the size distribution of particulate matter (PM).
  • Exposure in proximity to selected freeways with either heavy diesel or gasoline-powered vehicles will cause exacerbation of inflammatory airway health effects, and exposure to ultrafine particles at very close proximity to a freeway will result in the most severe effects.

Progress Summary:

Ultrafine PM consists of primary-source particles mostly emitted by combustion associated with motor vehicles. Because of their lack of mass, ultrafine particles have been impossible to collect in measurable amounts over practical time intervals. Also, the very small size of these particles has prevented determination of their size distribution. These two problems have been solved by implementing two technologies in series, an ultrafine concentrator and a recently developed cascade impactor, the NanoMOUDI. The combined concentrator/NanoMOUDI system has been employed in the field at two different locations to collect the ultrafine particles at morning (rush hour), afternoon (chemical reactions/agglomeration), and evening (rush hour). Results on the size distributions as well as the chemical constituents in each size range are unique.

We have been conducting a series of animal exposures to concentrated ambient particles (CAPs) in discrete distances from a freeway as well as collecting size-fractionated PM for in vitro studies. We have measured the physicochemical and biological characteristics of PM as a function of distance from freeways. Specifically, the size distribution of PM was measured 10, 30, 50, 100, 150, 500, and 1,000 m downwind and 10 m upwind from the freeway. Elemental carbon (EC), nitric oxide (NOx), and carbon monoxide (CO) were measured in these locations. Finally, the vertical profile of PM concentrations was measured. Our results defined a “zone of influence” of the freeway beyond which the number concentrations of PM decrease sharply. Concentrations of PM, EC, CO, and NOx were found to decrease exponentially with distance from the freeway. The fastest decrease in concentration occurs for particles in the range of 5-20 nm, which coagulate rapidly to form larger particles. We have demonstrated that particle coagulation occurs within the first 30-40 m from the freeway (see Figure 1).

Figure 1. Relative Particle Number, Mass, Black Carbon, CO Concentration versus Downwind Distance From Freeway 405

Figure 1. Relative Particle Number, Mass, Black Carbon, CO Concentration versus Downwind Distance From Freeway 405

We will continue to study the following hypotheses in relation to ultrafine particles: (1) a physical model can be developed to predict the changes in size distribution and number concentration of ultrafine particles as they are carried away from a freeway by the wind; and (2) ambient ultrafine particle concentration adjacent to a freeway can be predicted from traffic density and speed together with meteorological factors.

Future Activities:

Over the next 3 years, we will conduct vertical profiles of ultrafine particle concentration and size distribution, and horizontal profiles at locations near other freeways that have a high volume of diesel trucks. All of these results will be used to develop a model that predicts exposure to ultrafine particles from freeways in terms of traffic density, topography, and meteorology.

Journal Articles:

No journal articles submitted with this report: View all 13 publications for this subproject

Supplemental Keywords:

airborne particulate matter, aerosol, size distribution, particle concentrator, NRC priorities, mechanism, quinones, allergens, bioaerosols, dosimetry, children’s study, indoor exposure, exposure assessment, ultrafine, fine and coarse particles, regional human exposure model, REHEX, asthma, polycyclic aromatic hydrocarbon, PAH, clinical human exposures, source-receptor, measurement error, study design, susceptible populations, geo-code, toxicology, epidemiology, regional modeling, source/receptor analysis, Southern California, Los Angeles Basin, photochemistry, meteorology, trajectory modeling, peroxides, Southern California Particle Center and Supersite, SCPCS, air, geographic area, scientific discipline, health, RFA, susceptibility/sensitive population/genetic susceptibility, biology, risk assessments, genetic susceptibility, health risk assessment, biochemistry, particulate matter, environmental chemistry, mobile sources, state, aerosols, automotive exhaust, exposure assessment, California (CA), environmentally caused disease, engine exhaust, environmental hazard exposures, airborne urban contaminants, freeway study, allergen, indoor air, indoor air quality, allergens, particle concentrator, air quality, diesel exhaust, particulate emissions, human health risk, toxics, human health effects, particulates, sensitive populations, toxicology, automobile exhaust, diesel exhaust particles, environmental triggers, air pollution, airway disease, atmospheric chemistry, children, automotive emissions, exposure, inhaled particles, motor vehicle emissions, asthma triggers, PM characteristics, traffic density, ambient aerosol, asthma, human exposure, PM, particle transport,, RFA, Health, Scientific Discipline, PHYSICAL ASPECTS, Air, Geographic Area, particulate matter, Environmental Chemistry, Health Risk Assessment, State, Risk Assessments, mobile sources, Biochemistry, Physical Processes, urban air, engine exhaust, atmospheric particulate matter, atmospheric particles, motor vehicle emissions, airway disease, exposure, automobile exhaust, particulate emissions, automotive emissions, air pollution, automobiles, automotive exhaust, diesel exhaust, air sampling, human exposure, ultrafine particulate matter, PM, diesel exhaust particles, frreway study, California (CA), PM characteristics, human health risk

Relevant Websites:

http://www.scpcs.ucla.edu Exit

Progress and Final Reports:

Original Abstract
  • 1999
  • 2000
  • 2002 Progress Report
  • 2003 Progress Report
  • 2004 Progress Report
  • 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)