A method is proposed for quantitative analysis of atmospheric OH using a titration technique. The method uses a mixture of two gases: the titrant gas which is destroyed predominantly by reaction with OH on a time scale of a few days or less; and the dispersant gas which is inert essentially and is used to determine the dispersion rate of the mixture once it is released into the atmosphere. The rate of change of the ratio of the concentrations of the titrant and dispersant gases can be related to the local OH concentration. Measurements of this ratio are made for an hour or so after release of the mixture. A hypothetical example is given which utilizes a mixture of two halocarbons measured using a gas chromatograph with an electron-capture detector.