Examples of local background estimates. Time series (panel b) and histograms (panel c) of ethane with examples of stationary data (1), mobile data with a constant background (2), and mobile data with a variable background (3). Lognormal fits of each histogram (black dotted line) and the mode of the log normal fit (red dotted line) are displayed. Panel a contains a 1-Hz time series for ethane from one example sampling day. The log normal mode fits, 10^th, 35^th, and 60^th percentiles are overlaid on the 1-Hz time series for comparison. DOI: https://doi.org/10.1525/elementa.182.f2