单项选择题
A.<50mg/m3 B.<100mg/m3 C.<150mg/m3
A.不大于1m/s B.不大于2m/s C.不大于3m/s D.不大于10m/s
A.高于热风压力0.15MPa B.大于热风压力0.25MPa C.大于热风压力0.10MPa