Potassium Iodide Measurement Method -
History of Ozone and Oxidant Ambient Air Quality Standards

This page last reviewed March 8, 2005

From 1959 to 1975, "Oxidant" concentrations in air were analyzed using ARB's version of the potassium iodide method, which used a 2 percent neutral buffered potassium iodide reagent. This method measured oxidizing compounds that react with the reagent, potassium iodide, but not with the common oxygen molecule found in air. The air quality data produced by this method provided useful correlations with eye irritation, visibility effects and crop damage. In 1959, the "Oxidant" group was thought to include ozone, nitrogen dioxide and other photochemical gases and aerosols, including oxidizing hydrogen-based compounds. In 1969, the group of compounds included in the "Oxidant" group was thought to include ozone, peroxides and peroxyacyl nitrates, but not nitrogen dioxide (see NO2 Standard and History); the air quality standard document further stated that a correction factor was added for the measurement of nitrogen dioxide.

For more information, please contact Dr. Linda Smith at (916) 327-8225.

Ozone History