As an employee of the los angeles air quality commission, you have been asked to develop a
model for computing the distribution of no2 in the atmosphere. the molar flux of no2 at the
ground level ,0,
′′ is presumed known. this flux is attributed to automobile and smoke stack
emissions. it is also known that the concentration of no2 at a distance well above ground level is
zero and that no2 reacts chemically in the atmosphere. in particular, no2 reacts with unburned
hydrocarbons (in a process that is activated by sunlight) to produce pan (peroxyacetylnitrate), the
final product of photochemical smog. the reaction is first order, and ocal rate at which it
occurs may be expressed as = −kca(a) assuming steady-state conditions and a stagnant atmosphere, obtain an expression for the
vertical distribution ca(y) of the molar concentration of no2 in the atmosphere.
(b) if an no2 partial pressure of pa = 2*10-6
bar is sufficient to cause pulmonary damage, what
is the value of the ground level molar flux for which you would issue a smog alert? you
may assume an isothermal atmosphere at t=300 k, a reaction coefficient of k1=0.03 s-1
,
and an no2-air diffusion coefficient of dab = 0.15*10-4 m2
/s.