Abstract. A natural emissions inventory for the continen-tal United States and surrounding territories is needed in or-der to use the US Environmental Protection Agency Com-munity Multiscale Air Quality (CMAQ) Model for simu-lating natural air quality. The CMAQ air modeling sys-tem (including the Sparse Matrix Operator Kernel Emissions (SMOKE) emissions processing system) currently estimates non-methane volatile organic compound (NMVOC) emis-sions from biogenic sources, nitrogen oxide (NOx) emis-sions from soils, ammonia from animals, several types of particulate and reactive gas emissions from fires, as well as sea salt emissions. However, there are several emission categories that are not commonly treated by the standard CMAQ Model system. Most notable among these are ni-trogen oxide emissions from lightning, reduced sulfur emis-