Can a source net out of offsets for nonattainment pollutants?
The dual source definition applies to the offset trigger for nonattainment pollutants. This is current APCD practice. Thus, the determination of whether offsets are triggered for nonattainment pollutants is a two step process. First, the net emission increase of a proposed modification is calculated. If the modification by itself triggers offsets, then offsets apply. If the modification by itself does not trigger offsets, then the net emission increase from the modification is added to net emission increase for the entire source. If the net emission increase for the entire source exceeds the offset trigger, then offsets are required. Netting is allowed on the calculation of source wide net emission increase. That is, creditable decreases at a source can be used to reduce the net emission increase resulting from a modification to avoid triggering emission offset requirements.
