戴适当口罩（能尽量减少空气污染和口罩带来的伤害）。当人体空气净化器，为全人类的环保事业做“奉献”，另说。一定症状的出现，变相提高机体，免疫能力的同时；也相应程度摧毁该机体，正常的防御机理。
厕所养鸡，同理。
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Wear an appropriate mask (to minimize air pollution and the harm caused by the mask). As a human body air purifier, make "Contribution" to the cause of environmental protection for all mankind, another said. The emergence of certain symptoms, while improving the body's immunity ability in disguise; also destroys the body's normal defense mechanism to a corresponding extent.
In the toilet to raise chickens, same reason.