Ultraviolet (UV) radiation drives the chemistry of the troposphere by photolyzing molecules into more reactive species. A numerical simulation using the Tropospheric Ultraviolet-Visible (TUV) model version 3.6 and the Master Mechanism (MM) of the Gas Phase Chemistry model version 2.2 contrasted t... Show moreUltraviolet (UV) radiation drives the chemistry of the troposphere by photolyzing molecules into more reactive species. A numerical simulation using the Tropospheric Ultraviolet-Visible (TUV) model version 3.6 and the Master Mechanism (MM) of the Gas Phase Chemistry model version 2.2 contrasted the effects of high radiation in Mexico City and low radiation in Amsterdam on the chemistry in environments highly polluted with nitrogen oxides (NOx) and hydrocarbons. The chemistry illustrated nonlinear complexity. The high NOx limits ofthe self-cleaning capacity (or oxidizing capacity) of the troposphere were examined. The 0₃ began decreasing at 40 ppb NOx in Mcxico City and 35 ppb NOx in Amsterdam. 0₃ concentrations varied by less than 11 % between the two cities. The OR" concentrations began decreasing prior to the maximum of 0₃, at approximately 20 ppb in both cities. OH· concentrations were two times greater in Mexico City, reaching a maximum at 25.6 x 106 molecules cm-3. This leads to the conclusion that OR" is sensitive to UV -B radiation, or more specifically to the rate of photodissociation of 0₃ (J0₃), and 0₃ is not. Future work in this area is necessary to elucidate the complete mechanism. Show less
