The charts and graphs on this Web site are prepared using data that has been provided by Koch to public agencies, such as the Minnesota Pollution Control Agency and the US Environmental Protection Agency. Emissions measurements Koch's permits specify the way in which Koch samples and analyzes emissions. If Koch wishes to use a different analysis, or to vary the way an analysis is done, it must receive express written approval from the MPCA prior to making the change. Some of the newer heaters also have continuous NOx monitors, and all large heaters will shortly be equipped with such monitors, in accordance with the 2000 Clean Air Agreement. All of these sources also measure air flow and temperature, so that the actual pounds of emissions are measured directly.
Quality assurance is a large part of the monitoring effort.
Air monitors which measure emissions directly are electronically calibrated daily, inspected daily or weekly, audited quarterly using certified gas samples, and certified annually by comparing results to another EPA calibrated monitor. Koch measures wastewater emissions directly as well. Every day, a sampler automatically takes a sample every hour or so and a 24-hour composite sample is analyzed for chemicals regulated under the water discharge permit. Concentrations of pollutants are measured in Koch's laboratory. Duplicate, replicate, sample and lab blanks are run routinely for quality assurance.