Ultrafine Particle Concentrations in and Around Idling School Buses

Details

• Personal Author:
  Fischer HJ ; Weiss RE ; Zhang Q ; Zhu Y
• Description:
  Unnecessary school bus idling increases children's exposure to diesel exhaust, but to what extent children are exposed to ultrafine particles (UFPs, diameter < 100 nm) in and around idling school buses remains unclear. This study employed nine school buses and simulated five scenarios by varying emissions source, wind direction, and window position. The purpose was to investigate the impact of idling on UFP number concentration and PM2.5 mass concentration inside and near school buses. Near the school buses, total particle number concentration increased sharply from engine off to engine on under all scenarios, by a factor of up to 26. The impact of idling on UFP number concentration inside the school buses depended on wind direction and window position: wind direction was important and statistically significant while the effect of window positions depended on wind direction. Under certain scenarios, idling increased in-cabin total particle number concentrations by a factor of up to 5.8, with the significant increase occurring in the size range of 10-30 nm. No significant change of in-cabin PM2.5 mass concentration was observed due to idling, regardless of wind direction and window position, indicating that PM2.5 is not a good indicator for primary diesel exhaust particle exposure. The deposition rates based on total particle number concentration inside school bus cabins varied between 1.5 and 5.0 h-1 across nine tested buses under natural convection conditions, lower than those of passenger cars but higher than those of indoor environments. [Description provided by NIOSH]
• Subjects:
  Air Pollution Occupational Health Particulate Matter Safety Transportation Vehicle Emissions
• Keywords:
  Air Pollution Author Keywords: Ultrafine Particles Automotive Emissions Children Deposition Rate Diesel Exhausts Particulates PM2.5 School Bus Ultrafine Particles Wind Direction Window Position

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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
• Pages in Document:
  67-75
• Volume:
  69
• NIOSHTIC Number:
  nn:20055799
• Citation:
  Atmos Environ 2013 Apr; 69:67-75
• Contact Point Address:
  Yifang Zhu, Department of Environmental Health Sciences, UCLA Fielding School of Public Health, Los Angeles, CA 90095-1772, USA
• Email:
  Yifang@ucla.edu
• Federal Fiscal Year:
  2013
• Performing Organization:
  University of California Los Angeles
• Peer Reviewed:
  True
• Start Date:
  20050701
• Source Full Name:
  Atmospheric Environment
• End Date:
  20270630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:70d4ce9b7a7611f1ddd38a1d34646fb497d8a76a7a5b1c9ebafd571fe4c8e1c3dca8530c6a113ac83e0311e999249f627f9a3410c3f4c4043960700558ec1b82
• Download URL:
  https://stacks.cdc.gov/view/cdc/213568/cdc_213568_DS1.pdf
• File Type:
  [PDF - 664.39 KB ]