Regional, three-dimensional assessment of the ozone formation potential of organic compounds

A direct sensitivity analysis technique was used for three-dimensional atmospheric ozone formation potential (also termed reactivity) assessment in central California. Spatially and temporally resolved absolute and relative reactivities of 31 organic compounds and CO were calculated. In order to compare different species, the emissions of all the targeted organic compounds were perturbed equally. This perturbation followed the same spatial distribution as the total anthropogenic VOC emissions. Despite the variability (both spatial and temporal) in the absolute values, relative reactivities were fairly constant. Different types of domain-wide reactivity metrics were considered. All the three-dimensional metrics showed a high level of inter-species consistency among them and had a low day-to-day variability. Domain-wide metrics were comparable with box model scales, but showed a less dynamic inter-species behavior. Ranking of the three-dimensional metrics was very similar to the box model scales. It was also found that including the biogenic VOC emissions in the perturbation pattern has little effect on the results. Finally, local relative reactivities for six sites were fairly consistent in ranking but more variable than the domain-wide metrics.