Environmental Chamber Studies of Ozone Formation Potentials of Volatile Organic Compounds

Selected results of environmental chamber experiments carried out in the new large indoor environmental chamber at the University of California at Riverside (UCR) that are relevant to quantifying ozone impacts of volatile organic compounds (VOCs) are described. Issues and data needs for quantification of VOC reactivities towards ground-level ozone are described. The ability of the current SAPRC-99 chemical mechanism to simulate recent data from this chamber concerning the ozone formation from irradiations of an ambient reactive organic gas (ROG) NOx mixture and several new aromatics experiments are discussed. It was found that the mechanism consistently underpredicts ozone formation in ambient surrogate NOx experiments at low ROG/NOx ratios, and also underpredicts the effects of adding CO to aromatic NOx irradiations. The two problems may be related and suggest problems with the formulation of current mechanisms for atmospheric reactions of aromatics.