Ill. Admin. Code tit. 35 § 214.202
No owner or operator of an existing fuel combustion emission source shall comply with the emission standards of this Subpart by the use of dispersion enhancement techniques. Dispersion enhancement techniques shall include, but not be limited to, an intermittent control system or an increase of: stack height in excess of good engineering practice necessary to prevent downwash or fumigation conditions, stack diameter, exit gas velocity, or exit gas temperature, except as provided by Section 123 of the Clean Air Act ( 42 U.S.C.A. 7423 ) and regulations promulgated thereunder. Flue gas may be reheated where air pollution control equipment results in a reduction of flue gas temperature, provided that the degree of reheat does not exceed the temperature drop across such air pollution control equipment.
Ill. Admin. Code tit. 35, § 214.202
Amended at 7 Ill. Reg. 4219, effective March 28, 1983