A review of atmospheric ultrafine particles measurements and simulations

Base on the comprehensive literature review,this paper summarized the recent studies on measurements and simulations of atmospheric ultrafine particles in various regions and environments.The observations show that the time-spatial variations,formation and growth,compositions of ultrafine particles are strongly related to meteorological conditions and local pollution sources,therefore,the characteristic of ultrafine particles varied widely in different regions.The ultrafine particles can be directly emitted from combustion processes both stationary and mobile sources,or formed in the atmosphere through nucleation.Some aerosol dynamic module contained particulate number concentration diffusion models are introduced,but most of them are applied in a motor vehicle emission simulation.Little research has been conducted in applying particle number concentration simulation to city range.Finally,this paper provides and discusses the challenges to address the ultrafine particles pollution