ABSTRACT
Hydrogen sulfide may be present in the ambient atmosphere at concentrations of a few ppb or less. The reported odor detection threshold is in the 0.7 to 8.4 µg/m3 (0.5 to 6.0 ppb) range (1),(2). Concentrations in excess of 139 µg/m3 (100 ppb) are seldom encountered except as a result of an accident. Very high concentrations (of the order of several percent) of H2S may be present in geothermal gases (3). For the workplace environment, the ACGIH suggested exposure limit for H2S is 14 mg/m3 (10 ppm) at the time of preparation of this volume.
