Threshold limit value (TLV) means maximum permissible/acceptable concentration. TLV of phosgene in air is about ______________ ppm (parts per million)?
A. 0.002
B. 0.2
C. 1.2
D. 4.8
Threshold limit value (TLV) means maximum permissible/acceptable concentration. TLV of phosgene in air is about ______________ ppm (parts per million)?