Do ozone levels remain constant throughout the day?
No. In fact, they can be as different as, well, night and day. Because sunlight activates the ozone-forming chemistry, we typically see a 24 hour pattern of buildup and reduction. Overnight and early morning concentrations are usually quite low. A rapid increase normally follows until about noon, when concentrations tend to level off. Then, a second, rapid rise can occur later in the afternoon, with levels dropping sharply after sunset.
