"Stationary source" means any building, structure, facility, or installation which emits or may emit a regulated NSR pollutant. Emissions resulting directly from an internal combustion engine for transportation purposes or from a nonroad engine or nonroad vehicle as defined in section 216 of the CAA (42 U.S.C. 7550) are not a part of a stationary source.

(Source: Added at 49 Ill. Reg. 6237, effective April 23, 2025)