Sulphur dioxide is emitted at a rate of 2kg/s from the top of a chimney that is 120m high. The plume initially rises vertically a further 10m above the chimney exit, before being convected horizontally by a wind speed of 15m/s under conditions of neutral stability. The surrounding terrain is flat with a roughness length zo of 0.01m. Calculate;

 (a) The concentration (kg/m3 ) on the plume centre-line at a distance of 800m downwind of the chimney.[Answer: 5311 µg/m3 ] 

(b) The ground level concentration at a distance of 800m downwind of the chimney (that is, along the x-axis). [Answer: 257 µg/m3 ] 

(c) The location (x) where the maximum ground level concentration occurs downwind of the chimney on the xaxis. [Answer: 1542.3 m] 

(d) The concentration at this location. [Answer: 1051 µg/m3 ]