RBsumk.-La spectroscopie Mossbauer a et6 utilisee pour l'allalyse de poussi6res atmospheriques collectees par filtration. Nous avons identifik divers composBs du fer en nombre et en proportions variables suivant le degr6 de pollution de la zone de pr616vement. En particulier les aerosols provenant de I'kosion naturelle ont pu etre discriminks de ceux issus de sources anthropogeniques.

The particle size distribution of lead, bromine, chlorine, and calcium in exhaled aerosols from a human subject breathing normally polluted air has been measured using proton-induced X-ray emission (PIXE) analysis. For all elements apparent respiratory disposition fractions decreased from both small and large particle sizes to a minimum near 0.5 µ aerodynamic equivalent diameter. A feasibility is demonstrated for direct determinations of trace element respiratory depositions in human subjects breathing aerosols at ambient air concentrations.

Volatile elements from a basalt and from an obsidian were identified following slow neutron irradiation of the samples and a gamma ray spectroscopic assay of the room temperature distillate. The covariance of the enrichment factors for a variety of metals in the distillate and in atmospheric aerosols suggests that natural volatilization is responsible in part for the metal burdens in the atmosphere.

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Abstract-Respiratory response to inhalation of fine particles has been investigated for the aerosol generated by welding. Particles were sampled using a pair of 5-stage cascade impactors operating at 1 l./min flow rate. The subject exhaled into one impactor through an air ballast arrangement, and the other impactor simultaneously sampled the surrounding air. Particle size fractions were analyzed for principal elemental constituents from sulphur to lead using proton induced X-ray emission, PIXE. The results indicated a complex respiratory response, including both increase in particle size due to exposure to high humidity in the respiratory tract and deposition of particles during inhalation. The response was found to be different for the element group Mn, Cr, Fe, Ni compared to the group K, Ca, Ti by observing the associations among the elements as a function of particle size in the inhaled and exhaled aerosol. However, for respiratory deposition efficiency alone in all runs averaged together, no systematic differences between the different elements are demonstrated at the 99 % confidence level.

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