Benzene concentrations (ppb) at one background and one compliance well. Four observations per month for each well. Background well sampled in months 1,2, and 3; compliance well sampled in months 4 and 5.
EPA.92c.benzene2.dfA data frame with 20 observations on the following 3 variables.
Benzenea numeric vector of benzene concentrations (ppb)
Montha factor indicating the month of collection
Well.typea factor indicating the well type (background vs. compliance)