Generation of polydisperse KCl aerosol with a new salt aerosol generator was investigated.Special attention was paid on particles with diameters between 3 and 10 μm.The main improvement consists of the different routes of KCl solution droplets.In traditional generators,the solution droplets travel through one cylinder; while in the case analyzed here,after spray atomization,the droplets travel through two cylinders in series.The first cylinder was fed with warm air and the second one with cold air.In such way,the complete evaporation of the water from the droplets can be ensured.The influencing factors of the generated aerosol size distribution were investigated.The data measured show that the concentration of generated aerosol becomes higher both increasing the flow rate of the KCl solution injected in the first cylinder and increasing the concentration in the solution.The temperature of solution influences mainly the generation of smaller KCl particles(0.3-3 μm).The amount of hot air used in the generation process increases the concentration of larger KCl particles(＞3 μm)while cold air does not have the same effect.The aerosol generator is able to generate KCl aerosol stably.This instrument can be used effectively for testing air filters for automotive.