Air mainly contains nitrogen and oxygen, among which oxygen is the most needed by people, animals and plants, accounting for about 21%of air; If the oxygen content in the air drops to 16%, the burning candle will go out; If it is reduced to 7%, people and animals will soon suffocate. The air also contains vapor, carbon dioxide, sulfur oxides, nitrogen oxides, dust and other gases and substances. If the content of harmful gases and dust in the air is too high, the air will be polluted. The more these harmful gases and dirty things are mixed in the air, the more serious the air pollution is, and the greater the harm to people, animals and plants.
Air pollution leads to human respiratory diseases, leading to an increase in mortality. The mortality rate of lung cancer in heavily polluted areas of Chongqing is increasing year by year, exceeding 50 people/65,438+10,000, which is 4.7 times that in relatively clean areas. The mortality rate of lung cancer in individual blocks in Changsha is as high as 94 .36/65,438+10,000.
2, the greenhouse effect, the harm of climate warming to human body.
In recent decades, due to the influence of human activities, especially the sharp increase of energy consumption and the destruction of forests, the content of carbon dioxide in the air has been increasing, which has strengthened the greenhouse effect and made the global climate warm. This will increase the incidence of respiratory diseases, cancer, headaches and other diseases, and contribute to the occurrence and spread of tropical epidemics such as malaria.