I. Air pollution.
As a result of human activities or natural processes cause certain substances into the atmosphere, presenting a sufficient concentration for a sufficient period of time, and as a result, jeopardize the comfort, health and welfare of human beings or the environment of the phenomenon. Air pollution in our cities is still predominantly of the soot type, with the main pollutants being sulfur dioxide, carbon dioxide and soot.
Two, water pollution.
Water pollution is caused by harmful chemicals that reduce or lose the value of the use of water, polluting the environment water. China's cities and nearby rivers are still dominated by organic pollution, the main pollution indicators are petroleum, permanganate index and ammonia nitrogen.
Third, solid waste pollution.
Solid waste can be roughly divided into domestic garbage, general industrial solid waste and hazardous waste according to the source of three. China's urban solid waste pollution, including industrial waste, construction waste and domestic garbage.
Four, noise pollution.
. Since the industrial revolution, the creation and use of a variety of mechanical equipment, bringing prosperity and progress to mankind, but at the same time also produced more and more and stronger noise. Noise in most of our cities is at a medium level of pollution.
V. Soil pollution.
Pollutants generated by man-made activities into the soil and accumulated to a certain extent, causing the deterioration of soil quality, and then cause crops in some indicators exceed the national standard phenomenon, known as soil pollution. Soil pollution sources include the rotten application of chemical fertilizers and pesticides, industrial wastewater and waste residue, as well as domestic sewage and garbage.
Baidu Encyclopedia-Urban Environmental Pollution