1. a) Except as elsewhere provided in this Part, a person must not cause or allow the emission of sound during daytime hours from any property-line noise source located on any Class A, B or C land to any receiving Class A land that exceeds any allowable octave band sound pressure level specified in the following table, when measured at any point within the receiving Class A land. Sound pressure levels must be measured at least 25 feet from the property-line noise source.

   Octave Band Center Frequency (Hertz)	Allowable Octave Band Sound Pressure Levels (dB) of Sound Emitted to any Receiving Class A Land from
   	Class C Land	Class B Land	Class A Land
   31.5	75	72	72
   63	74	71	71
   125	69	65	65
   250	64	57	57
   500	58	51	51
   1000	52	45	45
   2000	47	39	39
   4000	43	34	34
   8000	40	32	32

2. b) Except as provided elsewhere in this Part, person must not cause or allow the emission of sound during nighttime hours from any property-line noise source located on any Class A, B or C land to any receiving Class A land that exceeds any allowable octave band sound pressure level specified in the following table, when measured at any point within the receiving Class A land. Sound pressure levels must be measured at least 25 feet from the property-line noise source.

   Octave Band Center Frequency (Hertz)	Allowable Octave Band Sound Pressure Levels (dB) of Sound Emitted to any Receiving Class A Land from
   	Class C Land	Class B Land	Class A Land
   31.5	69	63	63
   63	67	61	61
   125	62	55	55
   250	54	47	47
   500	47	40	40
   1000	41	35	35
   2000	36	30	30
   4000	32	25	25
   8000	32	25	25

(Source: Amended at 42 Ill. Reg. 20453, effective November 1, 2018)