How do weather conditions affect ground-level ozone?
[Back to Top] Sunlight, temperature, atmospheric stability, and wind conditions all affect the formation and accumulation of ground-level ozone. Ultraviolet radiation from sunlight drives the reaction between NOx and VOCs to form ozone, so ozone pollution increases on clear or partly cloudy days. Like many chemical reactions, ozone formation increases as temperatures rise. In addition, temperature affects ozone-forming emissions (e.g., evaporative emissions of VOCs and biogenic emissions increase with high temperatures). Atmospheric stability (temperature change by height) controls the amount of vertical air mixing that takes place. Strong stability tends to reduce mixing (dilution) of ground-level ozone and ozone-forming emissions. During atmospheric inversions, air higher in the atmosphere is warmer than air below, preventing lower air from rising and mixing. Inversions thus concentrate air closer to the surface, sometimes resulting in higher ozone levels. Wind conditions affect the
