Quality Assurance and Quality Control for State Air Toxics Emission Inventories

摘要

Minnesota Pollution Control Agency (MPCA) has compiled statewide air toxics emission inventories (ATEI) since early 1990s. Those emission inventories are used to model and evaluate monitored pollutant concentrations in air; identify and prioritize emission sources and pollutants to support environmental policy making and to educate general public; and provide emission data to the National Toxics Inventory (NEI) for the National-Scale Air Toxics Assessment (NATA). To serve those purposes the reliability of emission inventory is very important.For previous ATEIs, up to the preliminary draft of the 2011 ATEI, Minnesota worked with other Great Lakes States and Province of Ontario under the coordination of the Great Lakes Commission in the compiling the Great Lakes Regional ATEI, including the portion of MN state emission inventory. The quality assurance and quality control (QA/QC) at the regional level helped the improvement of state emission inventories. The Great Lakes Regional ATEI was ended at September 2013. Since then, Minnesota has focused more on its own QA/QC procedures and worked closely with US Environmental Protection Agency (EPA) to identify and correct errors. Although mercury belongs to air toxics, special attentions were paid to QA/QC Mercury emissions. This is because 99 percent of mercury load to Minnesota's lakes and streams is from atmospheric deposition.This paper provides background information on the Minnesota statewide ATEI program, describes QA/QC procedures performed to ATEIs by the MPCA, addresses typical issues found during the QA/QC processes, and discusses possible methods to resolve the problems. Examples for ATEI in general, as well as mercury emission inventory, for point sources are also provided. The QA/QC activities will be applied to the compilation of the coming 2014 ATEI and future. Those activities may also enlighten other states in the development of their respective ATEIs.