When does ozone concentration typically peak?

Ozone concentration typically peaks with sunlight due to the photochemical reactions that occur in the atmosphere. Ozone is formed in the Earth's atmosphere when sunlight drives a reaction between sunlight and pollutants such as volatile organic compounds (VOCs) and nitrogen oxides (NOx). During the day, particularly in the presence of strong sunlight, these reactions are enhanced, leading to higher concentrations of ozone in the lower atmosphere.

At night, the absence of sunlight reduces the energy available for these chemical reactions, resulting in a decrease in ozone levels. Similarly, during winter, cooler temperatures and less intense sunlight can lead to lower ozone production. Increased cloud cover can also lessen sunlight penetration, further inhibiting the photochemical processes responsible for ozone formation. Thus, the peak concentration of ozone correlates strongly with the intensity of sunlight available during the day.