(a) Compare and contrast the plume and puff models that describe the dispersion of materials released from sources. (4 Marks)

(b) Methyl isocyanate (MIC) is an intermediate compound in plants producing pesticides. In one of these plants a stack of an effective height of 100 m emits on a sunny day with a 2 m/s wind, a concentration of MIC 200m directly down wind measured at 5.0*10^-5 gm/ m3.

(i) Estimate the mass release rate of MIC in gm/s. State all necessary assumptions. (6 Marks)

(ii) If the TLV-TWA of MIC is 0.02 g/m3, would the workers in the plant be affected? (4 Marks)