Investigation of Atmospheric Reactivities of Selected Consumer Product VOCs

William P. L. Carter, Dongmin Luo, and Irina L. Malkina

Final Report to the California Air Resources Board
Contract No. 95-308
May 30, 2000

A series of environmental chamber experiments and computer model calculations were carried out to assess the atmospheric ozone formation potentials of selected organic compounds representative of those emitted from consumer products. This information is needed to reduce the uncertainties of ozone reactivity scales for stationary source emissions. The compounds studied were cyclohexane, cyclohexane, isopropyl alcohol, the three octanol isomers, diethyl ether, methyl ethyl ketone, cyclohexanone, methyl isobutyl ketone ethyl acetate, methyl isobutyrate, n-butyl acetate, and propylene glycol methyl ether acetate. “Incremental reactivity” experiments were carried out to determine the effect of each compound on O3 formation, NO oxidation and integrated OH radical levels when added to irradiations of reactive organic gas (ROG) - NOx representing simplified polluted urban atmospheres. Differing ROG surrogates and ROG/NOx ratios were employed to test how the impacts of the compounds vary with chemical conditions. In addition, single compound - NOx irradiations were carried out for the various ketones, OH radical rate constants were measured for the octanol isomers and propylene glycol methyl ether acetate, and the yields of the C8 carbonyl products were determined for each of the octanol isomers.

The results of these experiments were used in the development and testing of the SAPRC-99 mechanism that is documented in detail in a separate report (Carter, 2000). The data obtained, in conjunction with results of industry-funded studies of related compounds, has resulted in significantly reduced uncertainties in estimates of ozone impacts of the wide variety of oxygenated compounds present in consumer product emissions inventories. However, uncertainties still remain, and information is still inadequate to estimate ozone impacts for other classes of emitted compounds, such as amines and halogenated organics