Total Radical Production and Degradation Products from Alkene Ozonolysis

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Atmospheric composition is determined by a combination of emissions and chemical processing within the atmosphere. The removal of most hydrocarbons emitted to the atmosphere is initiated by reaction with the hydroxyl radical (OH). A series of degradation steps follows, leading eventually to CO2 and water. In the presence of nitrogen oxides, hydrocarbon oxidation leads to production of ozone / a pollutant harmful to human health, vegetation and materials. The extent to which ozone formation occurs depends upon details of the hydrocarbon oxidation steps. OH is formed naturally through the action of sunlight upon ozone. Following reaction with hydrocarbons, OH is converted into HO2 and RO2, hydro and organic peroxy radicals. RO2 and HO2 can then be converted back into OH if moderate levels of NO are present / an example of radical cycling. OH levels control the abundance of pollutants and global warming gases such as methane, and limit the rate of ozone production. To quantify these effects, we need to understand the processes which govern OH levels, while to predict the atmospheric impact of a given hydrocarbon, we must identify its degradation products / e.g., to assess if they have a long enough lifetime to be transported from their point of origin.