title: Improved Method for Analysis of Airborne Asbestos Fibers Using Phase Contrast Microscopy and FTIR Spectrometry.
abstract: BACKGROUND
  In recent years, some studies have tried to improve Phase Contrast Microscopy (PCM) for counting asbestos fibers. Due to the lack of a universally accepted alternative method, this study aimed to improve PCM for better counting of asbestos fibers.
  
  
  METHODS
  Confirmed asbestos standards were applied using a dust generator for sampling. Sampling from the dust generator was carried out according to the Occupational Safety and Health Administration (OSHA) ID-160 method and 95 samples with diverse densities were prepared to be counted using conventional and modern PCM. All samples were counted single blindly by a co-author of this study and the obtained data were analyzed by paired t-test, correlation coefficient and Bland-Altman analysis. Duplicate samples were prepared for qualitative analysis by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and X ray.
  
  
  RESULTS
  Asbestos densities on filters were in the range of less than 100 to 600 fibers/mm(2). Statistically, significant differences were observed for the count density of the 95 samples counted by the two phase contrast microscopes (P<0.001). Nikon microscope demonstrated higher counts compared to conventional microscope and had a lower coefficient of variation. Samples were analyzed qualitatively using FT-IR and SEM, and the presence of asbestos fibers was confirmed.
  
  
  CONCLUSIONS
  The improved PCM and FT-IR methods presented in this study demonstrated more precise and accurate determination of personal exposure to airborne asbestos fibers and subsequent risk assessment.
authors.affiliation: Safety Promotion and Injury Prevention Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran ; Department of Occupational Hygiene, College of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mansour R
authors.initials: MR
authors.lastname: Azari
authors.affiliation: Department of Occupational Hygiene, College of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Asil
authors.initials: A
authors.lastname: Yazdian
authors.affiliation: Department of Occupational Hygiene, College of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Rezvan
authors.initials: R
authors.lastname: Zendehdel
authors.affiliation: Safety Promotion and Injury Prevention Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran ; Department of Occupational Hygiene, College of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Hamid
authors.initials: H
authors.lastname: Souri
authors.affiliation: Department of Occupational Hygiene, College of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Soheila
authors.initials: S
authors.lastname: Khodakarim
authors.affiliation: Medical Nanotechnology & Tissue Engineering Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Habibalalah
authors.initials: H
authors.lastname: Peirovi
authors.affiliation: Department of Occupational Hygiene, College of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Davod
authors.initials: D
authors.lastname: Panahi
authors.affiliation: Department of Occupational Hygiene, College of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Marzieh
authors.initials: M
authors.lastname: Kazempour
keywords: Asbestos fibers; FT-IR spectroscopy; Phase contrast microscopy; Scanning electron microscopy