pbratios: Processing Pb isotope ratio data

#' Dataset with Pb isotope ratio data.
#'
#' The dataset was obtained processing a raw csv datafile with the functions provided by the package
#' \code{pbratios}.
#'
#' The dataset comprises PM10 samples collected from 2010 to 2014 at Ny-Ålensund (Svalbards,
#' Norwegian Arctic). Pb isotope ratios in this dataset were inspected for outliers and corrected
#' for mass bias using the standard bracketing technique.  Additionally, some QC control samples
#' labelled as \code{CRM482} are included in the dataset.
#'
#' @format The file has 148 observations and 9 columns. Columns are labelled as \describe{
#'   \item{\code{sample}}{ Sample name. The first 2 letters refer to the sampling location
#'   (\code{GB} = Gruvebadet), the next two numbers are a progressive index and \code{-XX} refers to
#'   the year of sampling.} \item{\code{Pb20x20y}}{ Four columns reporting Pb isotope ratio values
#'   for the ratios 208Pb/207Pb, 206Pb/207Pb, 208Pb/206Pb, 207Pb/206Pb.} \item{\code{Pb20x20y.U}}{
#'   Extended uncertainty (\eqn{U = k u} with \eqn{k = 2} for the 20xPb/20yPb ratio.} }
#' @author Andrea Bazzano and Marco Grotti.
#' @source Data were published in Bazzano, Cappelletti, Udisti and Grotti, Long-range transport of
#'   atmospheric lead reaching Ny-Ålesund: Inter-annual and seasonal variations of potential source
#'   areas. Atmospheric Environment, 2016, 139, 11-19.
#'
#' @examples
#' data(pm10nya)
#' summary(pm10nya)
#'
"pm10nya"