| (2) a 30-day rolling average limit. The owner or operator shall ensure compliance with a 30-day rolling average using: (A) a PEMS or CEMS under §117.140 of this title; or (B) a monitoring system that: (i) computes predicted emissions as a function of engine speed and torque using curves or equations supplied by the engine manufacturer or developed through engine testing, that: (I) may be adjusted by engine testing; and (II) must be shown to be consistent with the required initial and biennial compliance testing; and (ii) monitors and records data representative of engine torque and speed at sufficient frequency to accurately compute the 30-day average NOX . (f) No person shall allow the discharge into the atmosphere from any boiler or process heater subject to NO X emission specifications in subsection (a) or (b) of this section, CO emissions in excess of the following specifications: (1) for gas or liquid fuel-fired boilers or process heaters, 400 ppmv at 3.0% O2, dry basis; (2) for wood fuel-fired boilers or process heaters, 775 ppmv at 7.0% O2, dry basis; and (3) for units equipped with CEMS or PEMS for CO, the specifications of paragraphs (1) and (2) of this subsection apply on a rolling 24-hour averaging period. For units not equipped with CEMS or PEMS for CO, the specifications apply on a one-hour average. (g) No person shall allow the discharge into the atmosphere from any unit subject to a NOX emission specification in this section (including an alternative to the NO X limit in this section under §117.115 or §117.123 of this title) ammonia emissions in excess of 20 ppmv based on a block one-hour averaging period. (h) This section no longer applies to any gas-fired boiler or process heater after the appropriate compliance date(s) for emission specifications for attainment demonstration given in §117.9000(3) of this title. |
