Smoke - is formed in the process of fuel combustion gases (sulfur dioxide, carbon monoxide, etc.), ash, soot, as well as tar. The composition of the smoke entering the atmospheric air depends on the type of fuel, the method of combustion and the device of the furnaces. The emission of ash and smoke into the atmosphere is greater, the higher the ash content of the fuel. Shale (up to 50%) and low quality brown coal (up to 40%) have the highest ash content. The lowest ash content is in high-quality anthracite coal.
With smoke, atmospheric air also receives sulfur dioxide, the amount of which depends on the sulfur content in the fuel, and carbon monoxide, which is a product of incomplete combustion of carbonaceous substances. Large amounts of sulfur dioxide come from the combustion of oil, especially polysulphurous, but the main source of sulfur dioxide is coal, peat and shale.
Smoke is the most common air pollutant and can adversely affect the living conditions and health of the population. Soot contains resinous substances, which include carcinogenic compounds. Sulfur dioxide irritates the upper respiratory tract of a person and has a detrimental effect on vegetation, sometimes destroying large green areas. Carbon monoxide (see) is a strong poison for humans and animals. Therefore, the protection of the air of populated areas from pollution by smoke coming from emissions from power plants , boiler houses, when operating internal combustion engines is an important task. The main measures to reduce the content of harmful substances in the smoke are: burning high-quality fuel and converting all furnaces to burning gas; rationalization of the combustion process; cleaning of flue gases from ash and harmful impurities, etc. (see. Sanitary protection of atmospheric air ).