A photochemical theory of tropospheric ozone

We present a photochemical theory for tropospheric ozone in which the methane oxidation chain constitutes a large local source. This source produces about 10¹² odd oxygen molecules cm⁻² sec⁻¹ and implies a photochemical lifetime for ozone of about 1 day, much shorter than characteristic mixing times. The photochemical model reproduces the altitude and seasonal dependence of ozone at 30°N. It also gives qualitative agreement with observed day-to-day variations of the ozone density.