40 CFR 90.418 - Data evaluation for gaseous emissions.
For the evaluation of the gaseous emissions recording, record the last two minutes of each mode and determine the average values for HC, CO, CO2 and NOX during each mode from the average concentration readings determined from the corresponding calibration data. Longer averaging times are acceptable, but the reported sampling period must be a continuous set of data.
Title 40 published on 2015-08-22.
No entries appear in the Federal Register after this date, for 40 CFR Part 90.