Air pollution has become a serious problem in recent years.There are a lot of causes.first of all,is the chemical noxious gases emission.We all know that there are a lot of of factories around the world,they are actually emitting such gases everyday.The second one is the sharp decrease of the forests.Forest is very important to our Eco-system,it can adjust the heat and balance the air.The third one is the urbanization.People tend to stay in the city where is actually an abnormal Eco-system.Many cities do not have a complete system of controlling the air pollution.
In order to solve such problems,I have some ideas.
First of all is to control the emission of noxious gases.A set of necessary standards is required.It is not allowed to emit some particular gases until they have been transferred to another kind of chemical substance that is harmless to environment.Second one is planting more trees.We have cut down a lot of trees.It does have side effect on the quality of air.By planting more trees,many environment problems can be solved rather than air pollution only.
自己写的.累死了
