What is industrial smog primarily made up of?

Industrial smog is primarily made up of soot, which consists of particulate matter originating from the incomplete combustion of fossil fuels, particularly coal. When coal and other heavy fuels are burned in industrial processes, they release not only carbon dioxide but also a significant amount of particulate matter, including soot, ash, and various other pollutants. This mixture can combine with moisture in the air and lead to the formation of a dense, grayish fog, commonly seen in urban areas that are heavily industrialized.

Soot is particularly significant in the composition of industrial smog because it directly reflects the byproducts of burning carbon-rich materials. In contrast, chemical vapors, carbon dioxide, and ozone can be present in the atmosphere due to various industrial and vehicular activities, but they do not typically reflect the defining characteristics of industrial smog itself. Ozone is more associated with photochemical smog, occurring with sunlight and involving other reactions in the atmosphere, which further distinguishes it from the characteristics of industrial smog that are dominated by particulate matter like soot.