Smoke is the visible gas that comes out after incomplete burning of fuels. If a fuel is completely burnt, it gives off carbon dioxide, water vapour and free nitrogen, and does not give off any smoke. Smoke is generated only when fuels do not get proper conditions for combustion like enough oxygen and high temperature. Smoke generation is observed more in case of solid fuels like bituminous coal.
The gases generated after burning this coal, combine with dust and ash, and give rise to smoke. It causes a lot of harm to health, property and crops. It can even trap the sun-rays which is good for our health. Smoke inhalation is the primary cause of death in victims of indoor fires.
