Abstract: A severe fog-haze event occurred in late autumn and early winter in 2015 in North China.Vertical distribution of the mass and number concentrations of atmospheric particulate matter in Shunyi and Fangshan areas of Beijing during this event was analyzed using an Unmanned Aerial Vehicle (UAV) equipped with aerosol samplers and a laser particle counter.The results show that the number concentrations of aerosols with diameter less than 1.0 μm change little with the height,and those with diameter greater than 1.0 μm decrease slightly with the increasing height.This can explain that particle number concentration is relatively stable in the near-surface layer during heavy pollution events,with more submicron particles and smaller coarse particles in number concentration.The mass concentration is higher at the height of 50 m,with the maximum value of 700 μg·m^-3.