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19 Nov 2019
Ozone is also produced within the troposphere by oxidation of CO and hydrocarbons (principally CH4) in the presence of NOx. One of the earliest estimates of the global source of ozone in the troposphere was done by scaling the emission inventories of CH4 and CO. We repeat this calculation here. Consider the following mechanism for oxidation of CH4 and CO to CO2 under high-NOx conditions; Write a net reaction for the oxidation of Co to co2 by the above mechanism. Do the same for the oxidation of CH4 to co2 (some of the reactions may proceed more than once How many O3 molecules are produced per molecule of CO oxidized? per molecule of CH4 oxidized? Present-day global emission estimates are 3 times 1013 moles y for CH4 and 4 times 1013 moles 1 for CO. Using your results from question 2.1, estimate the global ozone the troposphere. The range o estimates for the global chemical production rate of ozone in the t as derived from 3-dimensional models of tropospheric chemistry, is 6-10 times 1013 moles yr-1. Explain how the approach you used in question 2.2 might be expected to overestimate the production rate of ozone. Conclude as to the relative importance of transport from the stratosphere and production within the troposphere as sources of tropospheric ozone.
Ozone is also produced within the troposphere by oxidation of CO and hydrocarbons (principally CH4) in the presence of NOx. One of the earliest estimates of the global source of ozone in the troposphere was done by scaling the emission inventories of CH4 and CO. We repeat this calculation here. Consider the following mechanism for oxidation of CH4 and CO to CO2 under high-NOx conditions; Write a net reaction for the oxidation of Co to co2 by the above mechanism. Do the same for the oxidation of CH4 to co2 (some of the reactions may proceed more than once How many O3 molecules are produced per molecule of CO oxidized? per molecule of CH4 oxidized? Present-day global emission estimates are 3 times 1013 moles y for CH4 and 4 times 1013 moles 1 for CO. Using your results from question 2.1, estimate the global ozone the troposphere. The range o estimates for the global chemical production rate of ozone in the t as derived from 3-dimensional models of tropospheric chemistry, is 6-10 times 1013 moles yr-1. Explain how the approach you used in question 2.2 might be expected to overestimate the production rate of ozone. Conclude as to the relative importance of transport from the stratosphere and production within the troposphere as sources of tropospheric ozone.