Field Comparison of P-Trak and Condensation Particle Counters

Details

• Personal Author:
  Hinds WC ; Kuhn T ; Nu Y ; Zhu Y
• Description:
  The P-trak ultrafine particle counter is a portable version of a condensation particle counter (CPC). Both instruments detect particle number concentrations in real time but have different detection limits. The P-trak has been widely used for indoor air quality evaluation and aerosol research. However, there is very limited information about the reliability and precision of this instrument and its comparability with other similar instruments. The purpose of this study was to compare a P-trak ultrafine particle counter with a standard CPC and evaluate its applicability to ambient air monitoring. This study was carried out near the Interstate 405 freeway (I-405) in Los Angeles. Measurements were made at increasing distances from the freeway on both sides at night as well as inside and outside of two 2-bedroom apartments located near the freeway. A CPC and a Scanning Mobility Particle Sizer (SMPS) were collocated with two P-traks and measurement results compared. In general, higher correlations were observed between P-trak and CPC data for indoor measurements than outdoor. The highest P-trak and CPC correlation (r2 = 0.9385) was detected inside Apartment 2, which is located farther away from the freeway than Apartment 1. The poorest correlation occurred at 30 m downwind from the freeway. In that case, the P-trak reported about 25% of ultrafine particle concentration that CPC did. A sigmoid (S-shape) function was fitted to observed P-trak to CPC ratios and geometric mean diameters of the corresponding ultrafine particle size distributions. Overall, we concluded the P-trak worked reasonably well when sampled indoor air. However, it has significant limitations in detecting freshly emitted ultrafine particles from vehicles. The P-trak underestimated ultrafine particles especially for particles smaller than its activation size which was found to be approximately 25-30 nm. Caution must be given in interpreting data collected by P-trak monitors near combustion sources. [Description provided by NIOSH]
• Subjects:
  Aerosols Air Pollution Environmental Monitoring Occupational Health Particulate Matter Safety
• Keywords:
  Air Pollution Air Sampling Equipment Air Sampling Techniques Automotive Emissions Particle Counters Particle Size Particulates Ultrafine Particles
• ISSN:
  0278-6826
• 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:
  422-430
• Volume:
  40
• Issue:
  6
• NIOSHTIC Number:
  nn:20058397
• Citation:
  Aerosol Sci Technol 2006 Jun; 40(6):422-430
• Contact Point Address:
  Yifang Zhu, University of California at Los Angeles, Department of Environmental Health Sciences, 650 Charles E. Young Drive South, Los Angeles, CA 90095, USA
• Email:
  Yifang@ucla.edu
• Federal Fiscal Year:
  2006
• Performing Organization:
  University of California Los Angeles
• Peer Reviewed:
  True
• Start Date:
  20050701
• Source Full Name:
  Aerosol Science and Technology
• End Date:
  20270630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:19f98e1ff96147766167b69728679c4bd869e25dc6194af6bb30a7185cf5fe35d4c46b9e8e0e7961fe576202363dea05fb9414eb976e5c75d67a2d2033f9eeae
• Download URL:
  https://stacks.cdc.gov/view/cdc/221504/cdc_221504_DS1.pdf
• File Type:
  [PDF - 495.20 KB ]