A ground level contamination source emits 0.45 g/s of a toxic gas into a 2.5 m/s wind. Assuming no initial rise of the gas at the point of release, what is the maximum ground-level concentration (in µg/m3) 500 m downwind from the source if the plume's standard deviations are oy = 76 m and oz = 38 m?

A paper plant is proposed for a location 1 km upwind from a town.  It will emit 40 g/s of hydrogen sulfide, which has an odor threshold of about 0.1 mg/m3.  Assume that winds at 10 m above ground are 2.5 m/s, and at the effective stack height they typically vary from 4 – 10 m/s blowing toward the town.  If it is summer day with a few broken clouds, What stack height should be used to assure concentrations are no more than 0.1 times the odor threshold at the near edge of town (1 km away)? To be conservative, the stack will be designed assuming no plume rise. Will any buildings (e.g., the country cabin or the doghouse on the far edge of town) experience higher concentrations than a residence at the 1 km boundary? Briefly explain your answer.

The rate of emission of SO2 from the stack of a power plant is 126.1 g/s. The effective heigth of the stack is 46m. Calculate the SO2 concentration in parts per million at a parking lot located 900 m downwind from the stack on a sunny October day when the wind velocity is 4 m/s. Use class C stability and rural conditions

The following is a well known formula for estimating the plume rise V.D[ u Ah = 1.5 +0.0096 Qp V.D The estimated plume rise with a stack gas having heat emission rate 2000 kJ/s, the wind speed 4 m/s, stack gas speed 8 m/s inside a stack diameter of 1 m at the top is