Sampling of inorganic gases and vapours

This paper summarizes some of the research and evaluations the Federal Occupational Safety and Health Administration (OSHA) in the United States has conducted regarding sampling and analysis of inorganic gases and vapours. In the USA, OSHA is responsible for enforcing regulations concerning personal exposure to toxic substances in the workplace. There are regulations or permissible Exposure Limits (PELs) for at least 50 compounds which can be considered as inorganic gases and vapours. The development or evaluation of numerous sampling and analytical methods for inorganic gases and vapours has been stimulated by the need to determine compliance with these PELs. The validation of a sampling method for OSHA use requires extensive testing within a laboratory setting and, if possible, field studies to assure effectiveness. This paper includes a summary of some of the sampling techniques used for inorganic gases and vapours, and an example of a field test evaluating commercially available products for mercury sampling. Classical sampling methods for OSHA compliance purposes are discussed as well as new approaches such as impregnated carbon bead or passive monitors. In addition, a sampling system which captures both the vapour and the particulate phase is currently in use. Sampling systems and the effect moisture (or lack of it) has on collection of some inorganic gases and vapours is discussed. A sampling strategy employing detector tubes is also included. In addition we have included a brief overview of measureing exposures to mixtures of inorganic gases and vapours, and how an industrial hygienist can determine the total amount of error associated with the measurement.