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 ground level, n"a,0 is presumed known. this flux is attributed to automobile and smoke stack emissions. it is also know 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 the local rate at which it occurs may be expressed as ra [mol/m3/s] = -k1*ca.