Photochemical oxidants creation potential

Photochemical Oxidants Creation Potential. This is a measure of the potential to generate smog and is expressed relative to ethene. 

POCP = photochemical oxidant creation potential (kg ethylene eq) Resource use... 

Photochemical oxidants creation potential. Photochemical smog is caused by the degradation of VOCs and nitrogen and is expressed in kg of ethylene. 

Laser flash photolysis and discharge flow measurements of the reaction rates of OH with several VOC have been made in a project designed to provide data for the determination of the photochemical ozone creation potentials of the VOC. In related studies, the mechanisms of the atmospheric oxidation of a wide range of compounds have been developed. Finally, objective techniques for extensive mechanism reduction, first applied in combustion chemistry, have been applied to tropospheric mechanisms. 

Together with the rate coefficients of primary oxidant attack ( which correspond to the lifetime of the parent compound) NOCON factors may be used in atmospheric chemical - dynamic modelling to derive photochemical ozone creation potentials (POCP - values) for the individual hydrocarbons. POCP- values are expected to be the primary assessment factors in photochemical smog abatement strategies. 

Thus, the main, long-lived intermediate formed in the atmospheric oxidation of benzaldehyde is nitrophenol. The oxidation involves two NO to NO2 conversions, but one of these NO2 species is then incorporated in the nitrophenol and so the route is inefficient at generating ozone. Furthermore, it leads to scavenging of NO in forming the nitrophenol. The net result is that benzaldehyde has a negative photochemical ozone creation potential, largely because of the NO c scavenging effect (Derwent et al., 1998). 

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