Comparison of NIOSH 5040 method versus aethalometer™ to monitor diesel particulate in school buses and at work sites

J. Borak, G. Sirianni, H. J. Cohen, S. Chemerynski, R. Wheeler

Research output: Contribution to journalArticlepeer-review


This study, undertaken initially to understand apparent differences between two recent reports of diesel particulate matter (DPM) inside school buses, involved side-by-side comparisons of two different methods for measuring ambient and occupational exposures to DPM. The NIOSH 5040 method yields time-weighted-average measurements of elemental carbon (EC) and organic carbon (OC), whereas the Aethalometer yields near-real time measures of carbonaceous particles (black carbon or BC) by optical absorption. The two methods were compared on three school buses and in three different work sites. Three side-by-side sampling configurations were used (open-faced filter with and without two different cyclones) in triplicate along with two or three Aethalometers. BC readings were correlated with results from openfaced cassettes, but there were statistically significant differences between the results of sideby- side Aethalometers. In addition, Aethalometer airflow rates were inaccurate, the instruments were sensitive to vibration, optical calibration could not be performed, and historically derived conversion factors to relate EC and BC were not appropriate. The Aethalometer could prove useful for monitoring of industrial work sites, but only after a method for external calibration and improvements in pump design and vibration isolation are developed.

Original languageEnglish (US)
Pages (from-to)260-268
Number of pages9
JournalAmerican Industrial Hygiene Association Journal
Issue number2
StatePublished - Mar 1 2003


  • Aethalometer
  • Diesel particulate matter (DPM)
  • NIOSH Method 5040

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health

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