The new high-power Electronic Nicotine Delivery System (ENDS) can generate aerosols with higher nicotine concentrations than older ENDS . Aerosol particle sizes affect deposition patterns and then plasma nicotine levels in vapers. Consequently, understanding the factors influencing particle size distribution of high-power ENDS is relevant to assess their performance in terms of nicotine delivery. The particle size distribution and the aerosol output (aerosol mass) were measured using cascade impactors. The effects of the refill liquid composition (80% PG/20% VG vs. 80% VG/20% PG; PG refers to propylene glycol and VG to vegetable glycerin) and the power level of the battery (from 7 W to 22 W) were investigated. The aerosol output increases significantly with the power level following a logarithmic law. The PG/VG ratio also has an impact on the aerosol output. The higher the VG content in the refill liquid, the higher is the aerosol output. Besides, particle size distribution is positively related to the power level, following linear correlations between the mass median aerodynamic diameter (MMAD) and the power level in the range of 7-22 W. A moderate impact of the PG/VG ratio on size distribution is equally observed. Changes in the power level allow the transition between a dominant mode with MMAD from 613 nm to 949 nm. We demonstrated that the power level can strongly change the aerodynamic properties of high-power ENDS, especially at high voltage. Associated with the aerosol nicotine level assessment, MMAD could be determined as a means for comparing ENDS devices and nicotine delivery.Read less <