Air Pollution
Air pollution happens when the air is contaminated by gasses such as gas from motor vehicles. Air can be contaminated by carbon monoxide, nitrogen oxide, sulphur dioxide, hydrocarbon, and soft particles like dusts. Some air pollutions happen naturally, for example, gas from volcanic activities. Mostly air pollutions happen because of combustion process in motor vehicles using fossil fuel. Combustion of coal to generate electricity releases tons of sulphur dioxides into the air. Sulphur dioxide and nitrogen oxide, together with vapor in the air and form acid rain.
Air pollution is also caused by forest burning. In Indonesia and India, farmers often do burn forest to open new farming areas. This practice also releases carbon monoxide into the atmosphere. Air pollution causes various impacts for plants, animals, and human.
Green House Effect
What will happen to the air inside a closed car which is parked and exposed to sunlight for a few hours? Radiation of sun energy heats the air in the car, makes the temperature inside much warmer than the outside. The car glass window, like a glass wall in a “green house”, restrains the heat inside the car.
Gasses in the atmosphere restrain a lot of radiation energy from the sunlight that reaches the earth surface. Land, sea, and everything on earth surface absorb the sun energy. Objects which have absorbed the energy reflect the heat energy to its surroundings. Air pollution in atmosphere traps the heat and causes the air temperature even hotter. The process of this heat restrain by atmosphere gasses is called green house effect. Without the green house effect, all sun’s energy will not be reflected to the surrounding objects, and earth will be too cold for living organisms to live and reproduce. One of the gasses that play important role on the green house effect is carbon dioxide.