Word Smog (smoky mist) comes from the fusion of the English words «smoke» - smoke and «fog» - fog. Smog - one of the most common types of pollution that can be seen clearly. It is formed by the reaction of products of incomplete combustion of fossil fuel such as coal with water droplets in the fog. Usually among carbon contaminants are CO2, nitrogen dioxide, sulfur dioxide NO2 S02 and other elements, and their reaction with the water drops in the mist form corrosive acids. As a result of inhalation of smog there is a sensation of breathlessness and cramps in the throat, a drop of acid attacks the mucous membranes of the respiratory tract that can cause (or worsen), asthma, chronic bronchitis, emphysema, as well as eye irritation and decreased immunity, or death. This is the smog in December 1952 in London that killed at various data from 4000 to 6000, which led to the emergence of the first laws aimed at preserving the environment.