It is widely accepted that humans have been a major cause of environmental problems since we began creating our cities and especially since the Industrial Revolution of the 20th century. All aspects of the Earth have been affected by humans' desire to conquer and dominate the planet. Our impact has gone beyond pollution to altering the functioning of many natural systems. These systems include our atmosphere, several land ecosystems and the complex water environments of which we get our drinking water and food sources. The effects have been universal ranging from ourselves to just every other living organism on this planet. Sure, it sounds like we have ruined everything and probably the best this to do is just prepare for the worst of the consequences, but there is a possibility for improvement if we start correcting things now. The very air that we breath in most major cities is considered unhealthy because of the contaminants that we put in the air through the burning of fossil fuels by our cars and industrial power plants. The residence time of these pollutants is what determines there affect. Some pollutants are only around for days like NOx with impacts that are largely local, when at levels above air-quality standard there are increases in the number of cases of respiratory disease. Others last a little longer, a few weeks, like SO2, which then are eventually removed from the atmosphere in the form of acid rain. These pollutants are relatively insignificant in comparison with their affect on humanity, like CO2 and CFCs who are around for centuries. These are the chemicals responsible for global warming and the ozone depletion. Also, coming from the burning of gasoline and diesel fuel is particulate matter, otherwise known as smog, when combined with any of the oxides they present a deadly combination for the health of all living organisms.Some these chemicals, namely carbon dioxide, also is a result of our d...