Indoor air pollution would include smoking, and heaters/air conditioners. In some cities and countries, such as Japan, children and adults have to wear gas masks due to their pollution problems. Burning of some fuels can cause carbon monoxide to be released into the air. Carbon monoxide is very dangerous and can kill a person in minutes.

The burning of fossil fuels causes massive amounts of carbon dioxide to be released into the air. The carbon dioxide then goes into the atmosphere. The increased amount of carbon dioxide may cause global warming. Global warming may lead to the melting of the ice caps and cause coastal cities to flood.