Ill. Admin. Code tit. 35, § 201.151 – Design of Effluent Exhaust Systems

a) No person shall cause or allow the operation of an emission source or of air pollution control equipment without providing one or more stacks or vents that are designed to prevent the concentration of any air contaminant from:
1. 1) Exceeding any applicable ambient air quality standard, either alone or in combination with air contaminants from other sources; or,
2. 2) Causing or tending to cause air pollution, either alone or in combination with air contaminants from other sources; or,
3. 3) Exceeding the emission standards and limitations of subchapter (c) of this Chapter.
b) Exception. This rule shall not apply to emission sources, such as stock piles of particulate matter which, because of the disperse nature of such emission sources, cannot reasonably be expected to be emitted through a stack.