This data set consists of in-situ measurements of arctic ambient aerosol particle (outside cloud) and cloud particle residual (inside cloud) aerosol properties observed during the ACLOUD campaign which took place during May/June 2017, which was part of the AC3 project. These measurements were made using the CVI inlet and PSAP, CPC and UHSAS aerosol instruments of the Leibniz Institute for Tropospheric Research (TROPOS) in Leipzig, Germany. The CVI flag 0 or 1 denotes ambient aerosol or cloud particle residual measurements, respectively, accomplished by a change in the sampling behavior of the CVI inlet. Measurements just after switching from one mode to another should be treated with caution, especially for the absorption coefficient values which have a time resolution of 30 sec. The given data sets are already corrected for the CVI enrichment factor, which should also be applied for measurements of other groups behind the CVI. Another correction for cloud particle residual measurements only is the CVI aspiration and sampling efficiency, which can be inferred from the comparison with the in-situ cloud particle measurements. Contact the PI and contact person Stephan Mertes for more information. Use only measurement data after takeoff and before landing of the Polar 6 aircraft. CVI inlet heating broke 2017-06-14T15:43:08, so that inlet freezing could have been occurred thereafter. Those periods are tried to identified and data deleted. The UHSAS two dimensional size distribution data is given in size bin diameter Dp (nm) in the header and the dN/dlogDp (cm-3 nm-1) value starting from column 13. The UHSAS instrument broke 2017-06-17T11:41:12. From this point in time no size distribution data are provided anymore. There is one file per flight. A detailed description of the data processing will be done in an upcoming data paper.