OZONE PRODUCTION EFFICIENCIES OF ACETONE AND PEROXIDES IN THE UPPER TROPOSPHERE

HOx concentrations in the upper tropical troposphere can be enhanced b y the presence of acetone and the convective injection of peroxides. T hese enhancements in HOx might be expected to increase ozone productio n by increasing the rate of the HO2 + NO reaction. We show however tha t the convective enhancements of hydrogen peroxide (H2O2) and methyl h ydroperoxide (CH3OOH) above steady state during the PEM West B campaig n were largely restricted to air parcels of marine boundary layer orig in in which the mean NO concentration was 8 pptv. The ozone production efficiencies of the two peroxides at such low NO concentrations are v ery small. Their impact on the ozone budget of the upper tropical trop osphere during PEM West B was therefore probably modest. Unlike the pe roxides, acetone in the upper tropical troposphere during PERI West B exhibited a positive correlation with NO. It also has a much larger oz one production efficiency than either H2O2 or CH3OOH. It therefore has a much greater potential for significantly increasing ozone productio n rates in the upper tropical troposphere.