Concentration and Size Distribution of Ultrafine Particles near a Major Highway

Details

• Personal Author:
  Hinds WC ; Kim S ; Sioutas C ; Zhu Y
• Description:
  Motor vehicle emissions usually constitute the most significant source of ultrafine particles (diameter <0.1 um) in an urban environment, yet little is known about the concentration and size distribution of ultrafine particles in the vicinity of major highways. In the present study, particle number concentration and size distribution in the size range from 6 to 220 nm were measured by a condensation particle counter (CPC) and a scanning mobility particle sizer (SMPS), respectively. Measurements were taken 30, 60, 90, 150, and 300 m downwind, and 300 m upwind, from Interstate 405 at the Los Angeles National Cemetery. At each sampling location, concentrations of CO, black carbon (BC), and particle mass were also measured by a Dasibi CO monitor, an aethalometer, and a DataRam, respectively. The range of average concentration of CO, BC, total particle number, and mass concentration at 30 m was 1.7-2.2 ppm, 3.4-10.0 ug/m3, 1.3-2.0 × 105/cm3, and 30.2-64.6 u/m3, respectively. For the conditions of these measurements, relative concentrations of CO, BC, and particle number tracked each other well as distance from the freeway increased. Particle number concentration (6-220 nm) decreased exponentially with downwind distance from the freeway. Data showed that both atmospheric dispersion and coagulation contributed to the rapid decrease in particle number concentration and change in particle size distribution with increasing distance from the freeway. Average traffic flow during the sampling periods was 13,900 vehicles/hr. Ninety-three percent of vehicles were gasoline-powered cars or light trucks. The measured number concentration tracked traffic flow well. Thirty meters downwind from the freeway, three distinct ultrafine modes were observed with geometric mean diameters of 13, 27, and 65 nm. The smallest mode, with a peak concentration of 1.6 × 105/cm3, disappeared at distances greater than 90 m from the freeway. Ultrafine particle number concentration measured 300 m downwind from the freeway was indistinguishable from upwind background concentration. These data may be used to estimate exposure to ultrafine particles in the vicinity of major highways. [Description provided by NIOSH]
• Subjects:
  Aerosols Environmental Monitoring Occupational Health Particulate Matter Safety
• Keywords:
  Air Monitoring Automotive Emissions Environmental Monitoring Particle Aerodynamics Particle Size Ultrafine Particulates
• ISSN:
  1096-2247
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  California ; OSHA Region 9
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  52
• Issue:
  9
• NIOSHTIC Number:
  nn:20057954
• Citation:
  J Air Waste Manage Assoc 2002 Sep; 52(9):1032-1042
• Contact Point Address:
  Dr. Hinds, University of California, Los Angeles, Department of Environmental Health Sciences, 650 Charles E. Young Dr. South, Los Angeles, CA 90095
• Email:
  whinds@ucla.edu
• Federal Fiscal Year:
  2002
• Performing Organization:
  University of California, School of Public Health, Los Angeles, CA
• Peer Reviewed:
  True
• Start Date:
  19990701
• Source Full Name:
  Journal of the Air and Waste Management Association
• End Date:
  20040630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:1cab113e080a38ee62c5fbf371669f773f9ad8f8e803fcd8c4bcc3eed674f1dbcb0e04b29416028aaf92b5f636292deddb363d1230d5e89a61b6032bc9383c3a
• Download URL:
  https://stacks.cdc.gov/view/cdc/215156/cdc_215156_DS1.pdf
• File Type:
  [PDF - 418.00 KB ]