Survey of gaseous pollutant concentration distributions in mineral collections

The concentration of four types of gaseous pollutants were semiquantitatively determined in samplings of cabinets from three mineral collections. The pollutants measured included: acidic vapours (thought to be primarily carboxylic acid vapours), mercury vapour, sulfur dioxide, and silver-tarnishing gasses (thought to be primarily hydrogen sulfide). These pollutants were monitored using simple and inexpensive monitors and/or dosimeters. Some of the monitors and dosimeters were commercially available, whereas others were specially fabricated and calibrated. The three investigated collections provided examples of three material combinations: metal drawers in metal cabinets, wooden drawers in metal cabinets and wooden drawers in wooden cabinets. Interpretation of pollutant concentrations as functions of position within the crystal- chemical classification system used to organise collection storage generally showed anticipated patterns. Several exceptions to these patterns, which have significant implications for collection care, were also noted. -- CCI