Air is one of the important environmental factors for human survival. The human body constantly exchanges gas with the external environment, inhales oxygen and spits out carbon dioxide. Usually, the content of carbon dioxide in the atmosphere is 0.04%, but due to the development of industry, the pollution to the atmosphere is intensified, and the content of carbon dioxide in the air of many cities is as high as 0.05% ~ 0.07%, and some even as high as 0.2%. According to research, when the concentration of carbon dioxide in the air is too high, people will feel uncomfortable breathing; When the concentration of carbon dioxide reaches 4%, there will be headache, tinnitus and high blood pressure; When the concentration of carbon dioxide reaches more than 10%, it will cause death. However, green plants can carry out photosynthesis in the sun, absorb carbon dioxide and release oxygen. The research shows that plants can produce 5 tons of oxygen for each growth 1 ton, and each hectare of forest can absorb 1 ton of carbon dioxide every day, producing 0.735 tons of oxygen. It can be said that green plants are a huge "oxygen factory".
Green plants are "detoxifiers"
Green plants can absorb harmful gases in the air and purify the polluted air. According to research, in areas with 30% green coverage, carcinogens in the air can be reduced by 58%, and sulfur dioxide can be reduced by more than 90%. Under the condition of sulfur dioxide pollution, the sulfur content of Ailanthus altissima leaves can exceed 29.8 times the normal content; One hectare of willow forest can absorb 720 kilograms of sulfur dioxide; Ginkgo, pine and cypress, pomegranate, palm, etc. , all have strong resistance to sulfur dioxide. Pittosporum can absorb hydrogen fluoride. These trees can also absorb toxic gases from automobile exhaust, and green plants can also absorb and filter radioactive substances.
Green plants are "sterilizers"
Cinnamomum camphora, Pistacia chinensis, pine, elm and Platycladus orientalis can secrete a volatile phytoncide, which can kill bacteria in the air. It is reported that the forests on the earth can emit 654.38+700 million tons of terpenoids into the atmosphere every year, and these aromatic substances have unparalleled bactericidal ability and exciting effect. Data show that there are as many as 300 species of trees that can secrete volatile phytoncide. 1 hectare of Sabina vulgaris can secrete as much as 60 kilograms of fungicides a day, and Chinese fir, pine and Paris polyphylla can secrete more; French phoenix tree, lemon, cinnamon tree, clove and walnut can also be secreted, which can kill diphtheria, tuberculosis, dysentery and other pathogens. When the area covered by green plants is large, the occurrence of diseases is obviously reduced.
Green plants are "vacuum cleaners"
Green plants can filter and absorb dust in the air and prevent industrial dust from spreading into the air. According to the measurement, when the atmosphere passes through the forest belt, the amount of dust and floating dust can be reduced by 32% ~ 52% and 30% respectively. Each hectare of spruce forest can absorb 32 tons of dust every year, and pine forest can absorb 36.4 tons of dust every year. With the reduction of dust in the air, respiratory diseases such as bronchitis, pharyngitis and pneumonia will also be significantly reduced.
Green plants are "silencers"
Green plants can scatter sound waves. When sound waves pass through leaves shaken by the wind, they can obviously weaken or make them disappear. The pores and coarse hairs on the surface of leaves, like the porous fiber sound-absorbing board in the theater, absorb noise. According to the measurement, the forest belt can absorb 20% ~ 26% noise and reduce its intensity by 20 ~ 25 decibels. Such as cedar, juniper and cypress, can absorb about 25% of the volume and reflect or refract about 50% of the noise at the same time, thus eliminating the noise and making the forest silent. When people rest in forests and flowers, their breathing, heart rate and blood pressure will slow down and decrease accordingly.