In the lower troposphere ozone is one of the components of p

In the lower troposphere, ozone is one of the components of photochemical smog. It is generated in air when nitrogen dioxide, formed by the oxidation of nitrogen monoxide from car exhaust, reacts by the following mechanism.
(1) NO2(g) NO(g) + O(g)
(2) O(g) + O2(g) O3(g)
Assuming the rate of formation of atomic oxygen in step 1 equals the rate of its consumption in step 2, use the data below to calculate the following quantities.
k1 = 7.0 10-3 s-1; [NO2] = 4.0 10-9 M
k2 = 1.0 106 L/mol

Solution

rate #1 = k [NO2]
Rate #1 = 5.0 10-3 s-1 [4.0 10-9 M]
rate #1 = 2.0 e-11

rate #2 = k[O] [O2]
rate #2 = 1.0 e6 [O] [1.0 e-2]

since rate #1 = Rate #2
rate #2 = 2.0 e-11

2.0 e-11 = 1.0 e6 [O] [1.0 e-2]
[O] = 2.0 e-15 Molar
that\'s your answer, assuming that k2 was 1.0 106 L/mol