7. What is photochemical smog?
This phenomenon was observed for the first time in the city of Los Angeles, United States, in 1943. Its origin is the combination of nitrogen oxides and volatile organic compounds from the exhaust of vehicles. The mixture, reacting under solar radiation, produces ozone and peroxyacyl nitrate, darkening the atmosphere. Photochemical smog is also characterized by its reddish-brown color. Its components are harmful to living beings and various materials. It can cause respiratory diseases such as rhinitis, bronchitis, asthma, pneumonia and other pathologies.