Section 243.107  Reference Conditions

All measurements of air quality, except PM_2.5 and lead, are corrected to a reference temperature of 25°C, and to a reference pressure of 760 millimeters of mercury (1013.2 millibars).  PM_2.5 and lead measurements shall be based upon the actual ambient air volume measured at the actual temperature and pressure at the monitoring site during the measurement period.

(Source:  Amended at 35 Ill. Reg. 18857, effective October 25, 2011)