The Role of Air Humidity in Variations in Near-Surface Ozone Concentration

Abstract

Measurements at the Tropospheric Ozone Research (TOR) station of Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, in 1994–2017 are used to study the dependence of variations in ozone concentration in the near-surface air layer on the absolute humidity. We found a neutral dependence at positive temperatures and surprisingly strong and sign-alternating variability at negative temperatures. The absolute air humidity negatively affects the ozone formation in the near-surface air layer, leading to decreased ozone concentration at temperatures of 0 to −30°C. At very low (below −30°C) temperatures the effect becomes positive, i.e., the ozone concentration increases with the absolute humidity.