Two principle sources of CO to the atmosphere are oxidation of CH4 and combustion. Mean rate constants for oxidation of CH4 and CO by OH in the...

Two principle sources of CO to the atmosphere are oxidation of CH4 and combustion. Mean rate constants for oxidation of CH4 and CO by OH in the troposphere are k1= 2.5 * 10-15 and k2 = 1.5 * 10-13 cm3 molecules-1 s- , respectively.  Observations indicate mean CO concentrations of 80 ppbv in the southern hemisphere, and a globally uniform CH4 concentration of 1700 ppbv. Calculate the fraction of CO source in each hemisphere contributed by oxidation of CH4. Comment on the interhemipheric difference.