Description: O2-O2, SO2, BrO, and IO differential slant column densities (dSCDs) measured by the University of Colorado Multi-AXis Differential Optical Absorption Spectroscopy (CU MAX-DOAS) instrument at Maido Observatory during April 29, 2018 and May 4, 2018. Instrument: University of Colorado Multi-AXis Differential Optical Absorption Spectroscopy (CU MAX-DOAS) Instrument reference: Coburn et al. (2011); doi:10.5194/amt-4-2421-2011 Instrument contact: Christopher F. Lee (christopher.f.lee@colorado.edu) Instrument PI: Rainer Volkamer (rainer.volkamer@colorado.edu) Measurement site: Maido Observatory, Reunion Island Longitude: 55.384 degrees East Latitude: 21.080 degrees South Altitude: 2160 meters above sea level Azimuth angle: Approximately 100 degrees clockwise from north The detection limit is defined as (2*Measured RMS) / (Maximum differential absorption cross section), where RMS = root-mean-square noise of spectral signal not accounted for by DOAS fit parameters [optical density units]. The maximum differential absorption cross sections used are 7.0e-21 [cm2] for SO2, 2.6e-17 [cm2] for BrO, and 3.5e-17 [cm2] for IO. Detection limits for SO2 dSCDs, BrO dSCDs, and IO dSCDs are only reported during periods of significant SO2 detection. BrO to SO2 ratios are only reported during periods when both BrO dSCDs and SO2 dSCDs are above the detection limit. Local time (RET) is UTC+4. Column 1: UTC start datetime (yyyy-mm-dd HH:MM:SS) Column 2: UTC center datetime (yyyy-mm-dd HH:MM:SS) Column 3: UTC stop datetime (yyyy-mm-dd HH:MM:SS) Column 4: Elevation angle above the horizon (degrees) Column 5: O2-O2 dSCD [molec2 cm-5] Column 6: Spectral fit error for O2-O2 dSCD [molec-2 cm-5] Column 7: SO2 dSCD [molec cm-2] Column 8: Spectral fit error for SO2 dSCD [molec cm-2] Column 9: Detection limit for SO2 dSCD [molec cm-2] Column 10: BrO dSCD [molec cm-2] Column 11: Spectral fit error for BrO dSCD [molec cm-2] Column 12: Detection limit for BrO dSCD [molec cm-2] Column 13: IO dSCD [molec cm-2] Column 14: Spectral fit error for IO dSCD [molec cm-2] Column 15: Detection limit for IO dSCD [molec cm-2] Column 16: Ratio of BrO dSCDs to SO2 dSCDs Column 17: Error in ratio of BrO dSCDs to SO2 dSCDs