Characterize the naive events. We estimate an emission source and rate for each naive event using the method from Daniels et al. . This allows us to more accurately quantify the CMS non-detect times in the following step. Briefly, we estimate the emission source by comparing CMS concentration observations to forward simulated concentrations from each possible source. For each naive event, the estimated emission source is taken to be the source whose simulated concentrations most closely match the actual concentration observations (assessed using correlation). We estimate an emission rate for each naive event by minimizing mean square error between the simulated concentrations and the CMS concentration observations over a range of possible emission rates.