| Factors affecting smog concentration 
            Smog concentrations vary over time
                and space according to environmental conditions
                and sunlight (the source of energy for
                photochemical reactions). The higher the sunlight intensity,
                the greater production rate of O3. The greater the wind speeds and
                mixing heights the lower the smog concentrationIn addition, the direction of the
                wind will control the areas where smog is
                transported. | 
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