A simple way to model air pollution over a city is with a box model that assumes complete
mixing and limited capability for the pollution to disperse horizontally or vertically except in the
direction of the prevailing winds. An example is a town located in a valley with an inversion
layer above it that prevents vertical convection. This inversion is at an altitude of 0.25 km. There
is a wind entering the town at a speed of 2.00 m/s; the town is 20.0 km wide perpendicular to the
wind and 25.0 km long in the direction of the wind; carbon monoxide is being emitted in the
town at a constant rate of 60.0 kg/s. Assume the carbon monoxide has a decay rate coefficient of
k = 0.10/hr. What is the steady-state concentration of cartoon monoxide in the town (in ppmv)?
Suppose a nearby storm passage causes the wind speed in the town to suddenly to 10.0 m/s.
What is the carbon monoxide concentration two hours later?
Solution
steady state concentration of carbon monoxide is =60/25
=2.4
one hour late the concentration will be zero.......