What is photochemical smog primarily composed of?

Photochemical smog is primarily composed of ozone and oxidized hydrocarbons. This type of smog forms when sunlight reacts with pollutants, such as volatile organic compounds (VOCs) and nitrogen oxides, in the atmosphere. These reactions produce ozone at ground level, which is a key component of photochemical smog. The presence of oxidized hydrocarbons, which include products formed from the chemical reactions of hydrocarbon emissions and natural atmospheric constituents, contributes to the characteristics of photochemical smog.

In urban areas, intense sunlight combined with high levels of vehicle emissions often leads to the formation of this type of air pollution. Ozone, while beneficial in the upper atmosphere for blocking harmful UV radiation, can be harmful to human health and the environment when present in the lower atmosphere, where it contributes to respiratory problems and damage to vegetation. The correct identification of this composition is crucial for understanding the processes that lead to air quality issues and the public health implications associated with photochemical smog.