How is O3 estimated quantitatively?
One of the quantitative method for estimating O3 gas is when ozone reacts with an excess of potassium iodide solution buffered with a borate buffer (pH 9.2), iodine is liberated. This iodine can be titrated against a standard solution of sodium thiosulphate.
2I–(aq) + H2O(l) + O3(g) → 2OH–(aq) + I2(s) + O2(g)