Abstract: Colorimetric indicators for breath, air, gas, & vapor analyses that can be thrown away after a single use, are easy to use, low cost, small, and simple to manufacture for indicating at least volume passed through the colorimetric indicators and may also be used to indicate concentration of an analyte within breath, air, gas, & vapor passed through the colorimetric indicators. The present invention is directed to colorimetric indicators for breath, air, gas, & vapor analyses. The colorimetric indicators may have a housing with an entrance port, an outlet, a volume indicator, and an analyte indicating reagent. The volume indicator may be a breath volume reagent. Different analytes may be measured, the analyte indicating reagent depending upon the particular analyte being to monitored. The breath volume indicator is colorimetric, and changes color when a predetermined volume of air is passed through the colorimetric indicators for breath, air, gas, & vapor analyses.