People always think that the water and air on the earth is endless, so they keep emitting million tons of waste gases into the sky and dumping numerous garbage into the rivers, lakes and oceans. As a result, human activities cause different types of environmental pollution. The clean-up of the garbage has become an important issue in many big cities. Among the million tons of garbage every day, most can not be incinerated or decayed, such as plastics, rubber and glass, which are considered as the number one enemy of mankind.
Marine pollution is mainly caused by the crude oil leaked from oil tanker and oil well, the pesticides and fertilizers used in agriculture, the sewage discharged from factories, and the acid solution exhausted from oil field. These wastes make most of the oceans and lakes polluted. As a result, not only the marine organisms are affected, but both the birds and humans may also be poisoned because of eating these organisms. Air pollution is the most direct and serious environmental pollution, mainly from the carbon monoxide and hydrogen sulfide emitted from factories, cars, power plants, and so on. Every day, there are many people infected with respiratory organ or visual organ diseases due to the exposure to these polluted air.
Water pollution happens when certain substance enters into the water and changes the chemical, physical, biological characteristics of the water, which then affects the efficient use of water, endangers human health, causes harm on the environment, and leads to the deterioration of water quality. Air pollution means that the concentration of pollutants in the air reaches to or above the hazardous level, which leads to the damage to ecosystems and the normal survival and development of human life. As a result, it will bring harms both on human being and creatures. Noise pollution is the phenomenon when the environmental noise exceeds the national emission standards of environmental noise, and interferences with the normal work, study, and living of other people.