Author(s)

Jeff Austin & Hien Tran

Abstract

Since the 1970's, air quality studies have shown that ozone concentrations increase on weekends at many locations. Most of these studies have focused on a specific region, and many of the studies have used simple statistical approaches which fail to yield conclusive evidence in the presence of strong random noise. We analyze day-to-day changes in daily peak ozone concentrations for three major urban areas in California using a more precise statistical approach, estimating percentage changes from day to day and examining spatial patterns among sites. We filter out trend and seasonality, explicitly account for serial dependency, and use robust statistics to reduce the effect of outliers. We fi

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