(a) Upon promulgation of this regulation, no owner or operator of an existing stationary combustion installation which fires oil or oil in combination with other liquid or gaseous fuels shall be allowed to emit particulate matter in excess of 0.10 pound per million Btu heat input. Within four years of the promulgation of this regulation, no owner or operator of an existing stationary combustion installation firing solid fuel shall be allowed to emit particulate matter in excess of 0.10 pound per million Btu heat input. Upon the commencement of operation, no owner or operator of a new stationary combustion installation shall be allowed to emit particulate matter in excess of 0.10 pound per million Btu heat input. The above emission limits apply to stationary combustion installations with a maximum heat input capacity equal to or exceeding:

1. (1) one million Btu per hour firing any amount of solid fuel; or
2. (2) fifty million Btu per hour firing oil or oil in combination with other liquid or gaseous fuels.