Because ultraviolet lamp in the emission of ultraviolet light at the same time will also produce a certain amount of ozone, the longer the time, the more the amount produced, too much inhaled ozone has harm to human health, in addition, ultraviolet light will kill some plants raised at home, if it is home disinfection, 30 minutes is enough, when driving ultraviolet light, people or animals at home should not move under ultraviolet light, and try to choose to use it when there is no one at home.