A.30mg/m3(20ppm) B.45mg/m3(30ppm) C.75mg/m3(50ppm) D.150mg/m3(100ppm)
A.閾限值 B.安全臨界濃度 C.危險(xiǎn)臨界濃度 D.4.3ppm以下
A.50% B.60% C.80% D.100%