Discussion Papers

Ozone Standard Exceedance Days in the South San Joaquin Valley

Jan de Leeuw and Shuojun Wang
This note analyzes ozone standard exceedance days in Bakersﬁeld, Arvin, Oildale, and Shafter since 1989. We have plotted violations of both onehour and eighthour federal and state standards (data from CARB monitoring stations). We have also drawn linear regression lines to estimate trend. They show a modest long term improvement (around 20%) in violations of onehour state standards, but generally a smaller increase in violations of eighthour state standards. They also show larger improvement in urban Bakersﬁeld than in the rural areas.

Jan de Leeuw
We introduce and discuss Principal Component Analysis (FPCA) of curves, using only relatively simple matrix algebra and optimization results. Diﬀerent loss functions, and various ways to impose constraints on the solution, are also discussed. The techniques are applied ﬁrst to some theoretical examples involving smooth curves, and subsequently to a data set with one year of hourly ozone measurements in Lebec, Kern County, California. R code for all functions, tables, and ﬁgures is included for reproducibility.

Jan de Leeuw
Data collected between February 2006 and February 2007 with an O3 and PM2.5 monitor in Lebec, California are analyzed. Extensive analysis is not possible, because of the short timespan, but we give descriptive statistics, mostly as plots. The influence of wildfires on PM2:5 and of I5 truck traffic is discussed briefly. It is noted that there are two schools in close vicinity. In order to get more information about longterm developments, including prediction, more extensive and systematic monitoring is necessary.

Month, Weekday, and Hour Effects in the Lebec Air Monitor Data

Jan de Leeuw
Data collected between February 2006 and February 2007 with an O3 and PM2.5 monitor in Lebec, California are analyzed. In this paper we analyze the data using simple least squares imputation, and an additive main effect model to look at the effects of montoftheyear, dayoftheweek, and houroftheday.