Method of measuring the total deposition efficiency of volatile aerosols in humans.

An exposure system was developed to measure the total deposition efficiency of airborne contaminants which may exist in the vapor, particle, or both phases of an inhaled atmosphere. A formula was derived to account for both deposition in the mouthpiece and one-way valve assembly and the volume of the assembly in the calculation of the total deposition efficiency. A human subject was exposed by mouth to three atmospheres containing either glycerol droplets with accompanying vapor, corn oil droplets of a similar size, or propylene glycol vapor. Analyses of the amounts of the exposure materials collected from a sample of the exposure air, collected from the exhaled air, and recovered from the mouthpiece provided the following average total deposition efficiencies: polydisperse 1 μm glycerol droplets and accompanying vapor 62%, polydisperse 0.8 μm corn oil droplets 19%, and propylene glycol vapor 100%. These experiments demonstrate that the total deposition efficiency of inhaled contaminants in both the particulate and vapor phases can be measured. Variations of deposition efficiency with type of material and aerosol mass concentration are discussed