Data Validation. In general, the NAEMS researchers invalidated measurement data if the data values were: • Unreasonably low or high when compared to normal ranges if there was supporting evidence that the data value is not correct (e.g., lagoon temperature sensor producing a reading of less than -40 ° C). • Obtained during system installation, testing or maintenance during which uncorrectable errors might be introduced. • Obtained when a sensor or instrument was proven to be malfunctioning (e.g., unstable). • Obtained during calibration or precision check of a sensor or instrument and before the sensor or instrument reached equilibrium after the check. • Obtained when the data acquisition and control hardware and/or software were not functioning correctly. Data that the NAEMS researchers deemed invalid were retained in the preprocessed data sets. However, the EPA did not use the flagged data to calculate pollutant emissions rates. For averaged data, data were invalidated to avoid errors introduced into calculated mean values due to partial-data days (e.g., only a few hours of valid data) that would result in biased time weights:
Appears in 2 contracts
Sources: Development of Emissions Estimating Methodologies for Lagoons and Basins at Swine and Dairy Animal Feeding Operations, Development of Emissions Estimating Methodologies