We then apply the spike detection algorithm from Daniels et al. to this maximum value time series, which uses a gradient-based method to identify sharply elevated concentration values, or spikes. We cluster all identified spikes into groups and background correct them by subtracting the average of the concentration values immediately preceding and following the groups. All other concentration values (that are not part of a group) are deemed background and are set to zero. The clustered groups of background-corrected enhancements are then taken as the naive emission events, referred to as the "naive events" throughout this article, and the "naive durations" are simply the lengths of these naive events.