(来学网)紫外线用于空气消毒时,其有效强度低于多少时应立即更换?()
  • A.
    (来学网)90μW/cm2
  • B.
    (来学网)80μW/cm2
  • C.
    (来学网)70μW/cm2
  • D.
    (来学网)60μW/cm2
  • E.
    (来学网)50μW/cm2