Ozone is one of the most important pollutants in the troposphere. Its concentrations are controlled by a complex process involving anthropogenic emissions, chemical reactions, and meteorology. It strongly affects human health, vegetation, and ecosystems in industrial, suburban, and rural areas worldwide. Tropospheric ozone has been steadily increasing over the last several decades, and its concentrations are expected to continue to increase throughout the 21st century as a result of increased fossil fuel use and population growth.

For all these reasons, studies that determine the behavior of ozone across a range of temporal and spatial scales are important. Interestingly, however, intraseasonal variability of surface ozone has yet to be comprehensively examined. It is possible that days with high ozone concentrations, particularly in locations with pronounced seasonal ozone cycles, correlate statistically with certain phases of the Madden-Julian Oscillation (MJO). In support of this hypothesis, a recent air quality study found statistically significant correlations between surface ozone concentrations and phases of the MJO in the Santiago, Chile metropolitan area. This presentation will report findings from that study as well as results from an extension of that methodology to over 130 surface ozone stations across the contiguous United States.