A device used to passively measure pollutant levels. Diffusion tubes contain a sorbent material treated with a chemical to produce a pollutant-specific colorimetric reaction. When the pollutant is absorbed, the chemical reacts to form a colored product. A reference chart is provided for comparison of the color intensity with approximate pollutant concentrations. Diffusion tubes are available for sulfur dioxide, nitrogen dioxide, formic acid and acetic acid. In general, diffusion tubes are inexpensive and easy to use but their detection limits are relatively high for museum environments. They may be useful for initial screenings of high pollutant levels in closed environments.
Synonyms and Related Terms
Diffusionsröhre (Deut.); tube à diffusion (Fr.);
Hazards and Safety
Multiple pollutants may cause inaccurate results.
P. Hatchfield, Pollutants in the Museum Environment, Archetype Press, London, 2002.