^ L/- | key source by **L**evel only | ^ -/T | key source by **T**rend only | ^ L/T | key source by both **L**evel and **T**rend | | -/- | no key source for this pollutant | | IE | emission of specific pollutant **I**ncluded **E**lsewhere (i.e. in another category) | | NE | emission of specific pollutant **N**ot **E**stimated (yet) | | NA | specific pollutant not emitted from this source or activity = **N**ot **A**pplicable | |* |no analysis done |