Smoke

People sometimes deliberately make smoke, for example as insecticide or smoke signals, or smoke screen to hide themselves in war, or as food flavoring and preservative. Some smoke is used to transmit drugs, as when tobacco or marijuana is smoked. Incense is smoke that is made for religious ceremonies or to smell good.

Smoke removal systems redistribute gas flows and reduce the temperature and concentration of smoke during a fire. This helps in evacuating people, limiting the spread of fire; and extinguishing the fire.

 Smoke from tobacco 
When people smoke tobacco in cigars or cigarettes, they are burning the tobacco and inhaling the smoke. Tobacco smoke can hurt the mouth, throat, and lungs. It can cause mouth, throat, or lung cancer. It can also cause emphysema and bronchitis (trouble breathing). They continue doing it because the smoke also has a nicotine.

 Smoke from factories 
Factories and power plants produce large amounts of smoke into the atmosphere which pollutes the air. Eventually the toxic chemicals in smoke fall to the ground, and then they pollute the soil and the water. When the air, soil and water are polluted with toxic chemicals, the chemicals also get absorbed by plants and animals (including humans).

Related pages
Dry ice
 Pollution

References

Category:Air pollution
Category:Fire
Category:Waste