UC Irvine

Because many aerosol hazards are dependent upon particle size, the American Conference of Governmental Industrial Hygienists established an Air Sampling Procedures Committee to ‘recommend size-selective aerosol sampling procedures which will permit reliable collection of aerosol fractions which can be expected to be available for deposition in the various major subregions of the human respiratory tract, e.g., the head, tracheobronchial region, and the alveolar (pulmonary) region.’ After reviewing available data on regional deposition of inhaled particles and on the collection efficiencies of sampling instruments, the committee recommends use of three particulate mass fractions for workplace sampling. Inspirable Particulate Mass applies to material which is hazardous anywhere in the respiratory tract; Thoracic Particulate Mass applies to materials which are hazardous anywhere within the lung airways and the gas exchange region; Respirable Particulate Mass applies to material which is hazardous only in the gas-exchange region of the lung. Each of these 3 mass fractions are defined and a procedure to provide guidance in establishing corresponding Particle Size-Selective Threshold Limit Values (PSS-TLVs) has been suggested. © 1988 The British Occupational Hygiene Society.