THE BASIS OF DUST SAMPLING IN OCCUPATIONAL HYGIENE: A CRITICAL REVIEW

Abstract

This paper sets out to examine the working criteria which should form the basis of good dust sampling practice in occupational hygiene. On the assumption that interest is nearly always focused on dust-related health effects once particles have entered the body, then the baseline for sampling should be the inhaled fraction, that is, that fraction of ambient airborne dust which enters the nose and/or mouth of the subject during the act of breathing. The dust fractions deposited in the various regions of the respiratory tract—nasopharyngeal (head), tracheobronchial and alveolated (respirable)—are expressed as subfractions of that inhaled fraction. For good sampling practice, a sampler should have an inlet whose characteristics for the entry of particles conform to those for the inhalability of the human head. Desired subfractions can be isolated inside the body of the sampler. The physical guidelines for designing such a sampler inlet are described and the performances of a number of practical sampling devices are discussed critically in the light of the suggestions made.