In-Cabin Commuter Exposure to Ultrafine Particles on Los Angeles Freeways

Worldwide people are exposed to toxic ultrafine particles (UFP, with diameters (dp) less than 100 nm) and nanoparticles (NP, dp < 50 nm) under a variety of circumstances. To date, very limited information is available on human exposure to freshly emitted UFP and NP while traveling on major roads and freeways. We report in-cabin and outdoor measurements of particle number concentration and size distributions while driving three vehicles on Los Angeles freeways. Particle number concentrations and size distributions were measured under different vehicle ventilation settings. When the circulation fan was set to on, with substantial external air intake, outside changes in particle counts caused corresponding in-cabin changes approximately 30-60 s later, indicating an maximal air exchange rate of about 120-60 h-1. Maximum in-cabin protection (~85%) was obtained when both fan and recirculation were on. In-cabin and outdoor particle size distributions in the 7.9-217 nm range were observed to be mostly bimodal, with the primary peak occurring at 10-30 nm and the secondary at 50-70 nm. The vehicle's manufacture-installed particle filter offered an in-cabin protection of about 50% for particles in the 7-40 nm size range and 20-30% for particles in the 40 to ~200 nm size range. For an hour daily commute exposure, the in-vehicle microenvironment contributes approximately 10-50% of people's daily exposure to UFP from traffic. (A)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/0013936X
• Authors:
  • ZHU, Y
  • EIGUREN-FERNANDEZ, A
  • HINDS, W C
  • MIGUEL, A H
• Publication Date: 2007-2-27

Language

• English

Media Info

• Pagination: 2138-2145
• Monograph Title: Photochemical Modeling of Emissions Trading of Highly Reactive Volatile Organic Compounds in Houston, Texas. 1. Reactivity Based Trading and Potential for Ozone Hot Spot Formation
• Serial:
  • Environmental Science & Technology
  • Volume: 41
  • Issue Number: 7
  • Publisher: American Chemical Society
  • ISSN: 0013-936X
  • EISSN: 1520-5851
  • Serial URL: http://pubs.acs.org/journal/esthag

Subject/Index Terms

• TRT Terms: Air; Environment; Measurement; Vehicle occupants; Vehicles; Work trips
• Geographic Terms: United States
• ITRD Terms: 6714: Air; 2455: Environment; 621: Journey to work; 6136: Measurement; 8122: USA; 1255: Vehicle; 1715: Vehicle occupant
• Subject Areas: Energy; Environment; Passenger Transportation; Vehicles and Equipment; I15: Environment;

Filing Info

• Accession Number: 01087412
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD
• Created Date: Jan 29 2008 10:30AM