Evolution of Particle Number Distribution Near Roadways. Part II: The ‘Road-to-Ambient’ Process

Details

• Personal Author:
  Hinds WC ; Sioutas C ; Wexler AS ; Zhang KM ; Zu YF
• Description:
  The 'road-to-ambient' evolution of particle number distributions near the 405 and 710 freeways in Los Angeles, California, in both summer and winter, were analyzed and then simulated by a multi-component sectional aerosol dynamic model. Condensation/evaporation and dilution were demonstrated to be the major mechanisms in altering aerosol size distribution, while coagulation and deposition play minor roles. Seasonal effects were significant with winters generally less dynamic than summers. A large number of particles grew into the >10 nm range around 30-90 m downwind of the freeways. Beyond 90 m some shrink to <10 nm range and some continued growing to >100 nm as a result of competition between partial pressure and vapor pressure. Particle compositions probably change dramatically as components adapt to decreasing gas-phase concentration due to dilution, so number distribution evolution is also an evolution of composition. As a result, people who live within about 90 m of roadways are exposed to particle sizes and compositions that others are not. [Description provided by NIOSH]
• Subjects:
  Aerosols Air Pollution Occupational Health Particulate Matter Safety
• Keywords:
  Aerosol Model Air Pollution Air Quality Air Quality Monitoring Author Keywords: Ultrafine Particles Automotive Emissions Freeways Particle Size Particulates Seasonal Factors Size Distribution Ultrafine Particles

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• ISSN:
  1352-2310
• 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:
  38
• Issue:
  38
• NIOSHTIC Number:
  nn:20057947
• Citation:
  Atmos Environ 2004 Dec; 38(38):6655-6665
• Contact Point Address:
  Anthony S. Wexler, Department of Mechanical and Aeronautical Engineering, University of California, Davis, CA 95616, USA
• Email:
  aswexler@ucdavis.edu
• Federal Fiscal Year:
  2005
• Performing Organization:
  University of California, School of Public Health, Los Angeles, CA
• Peer Reviewed:
  True
• Start Date:
  19990701
• Source Full Name:
  Atmospheric Environment
• End Date:
  20040630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:07b1c211771b4327090886298083f01bf7c2b5fd964d877494bb2ae1d033ab31985638692af6ff37f74904ec77c6e4e904ab613702e50af74c860145350b2f88
• Download URL:
  https://stacks.cdc.gov/view/cdc/215149/cdc_215149_DS1.pdf
• File Type:
  [PDF - 274.08 KB ]