The Enhanced Moderate Resolution Imaging Spectroradiometer (MODIS) Airborne Simulator (eMAS)instrument is maintained and operated by the Airborne Sensor Facility at NASA Ames Research Center in Mountain View, California, under the oversight of the EOS Project Science Office at NASA Goddard. The eMAS instrument is now a 38-channel instrument, sensing in the range from 0.445 to 13.844 um.The Enhanced MODIS Airborne Simulator (eMAS) L2 Aerosol Data product (eMASL2AER) consists of in-situ measurements of trace gas and aerosol emissions for wildfires and prescribed fires in great detail, relate them to fuel and fire conditions at the point of emission, characterize the conditions relating to plume rise, follow plumes downwind to understand chemical transformation and air quality impacts, and assess the efficacy of satellite detections for estimating the emissions from sampled fires. These measurements were collected onboard the DC-8 aircraft during FIREX-AQ, during summer 2019. The DC-8 aircraft had a comprehensive instrument payload capable of measuring over 200 trace gases as well as aerosol microphysical, optical, and chemical properties. The eMASL2AER product files are stored in Hierarchical Data Format (HDF-EOS). All gridded cloud parameters are stored as Scientific Data Sets (SDS) within the file.For more information and for a list of MAS campaign flights visit ladsweb at:https://ladsweb.modaps.eosdis.nasa.gov/missions-and-measurements/mas/or, visit the eMAS Homepage at:https://asapdata.arc.nasa.gov/emas/