单项选择题
臭氧用于医院空气消毒的最低浓度和作用时间分别为()。
A.≥20mg/m,≥30min
B.≥20mg/m,≥60min
C.≥50mg/m,≥30min
D.≥50mg/m,≥60min
E.≥100mg/m,≥30min
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单项选择题
A.≥20mg/m,≥30min
B.≥20mg/m,≥60min
C.≥50mg/m,≥30min
D.≥50mg/m,≥60min
E.≥100mg/m,≥30min
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