A) indoor sources of pollution in indoor air pollution sources are many, the metabolism of human breath, breathe through the body, speech and other activities into the indoor air pathogens, and the various objects contaminated product of combustion, such as the burning of tobacco. Pollution caused by the building itself.If the foundation distributed radon, ammonia [...]
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China total acreage resides in world third, but the average per person land area is only 0.777 hectare, is equal in the world average per person land 1/3; in 2000 China cultivated area 128,233,100 hectares, average per person cultivated area 0.101 hectare, insufficient world average per person farming half. The farming degree of utilization is [...]
Popularity: 16% [?]
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