Photochemical smog is a type of air pollution that occurs when sunlight reacts with pollutants like nitrogen oxides and volatile organic compounds. These pollutants are often emitted from vehicles, industrial facilities, and other sources. The reaction produces ground-level ozone and other harmful substances, leading to a hazy atmosphere and reduced air quality. This type of smog is most common in urban areas with heavy traffic and sunny weather. It can cause respiratory problems and other health issues for people, especially those with pre-existing conditions. Efforts to reduce photochemical smog often focus on decreasing emissions from automobiles and promoting cleaner energy sources.