{"tema_id":"394","string":"detection limit           #00151","created":"2022-12-19 09:13:30","code":null,"notes":[{"@type":"Scope note","@lang":"en-EN","@value":"(1) The detection limit is sometimes defined as an output signal equal to some other multiple (e.g., two or ten) of the noise level [2]. The noise level is the random background output signal of an instrument when sampling a blank or clean filtered air. (2) In this Document, the concentration of an airborne pollutant in either a gas or vapor phase is most often expressed in terms of the volume fraction of the pollutant in air: parts- per-million (ppm) [v\/v (10-6)]. Conditions of "},{"@type":"Cataloger's note","@lang":"en-EN","@value":"reference: D022:1991 3.6 "},{"@type":"Cataloger's note","@lang":"en-EN","@value":"ID: 00151 "},{"@type":"Definition note","@lang":"en-EN","@value":"the concentration of a substance that will yield a mean output signal equal to three times the mean short term noise level, as determined on a statistical basis "}]}