文摘
Particle number concentrations and size distributions are analyzed from 14 August to 18 November, 2014 in Lanzhou. The different diurnal variations are affected by their respective various sources, such as local emissions and NPF events. High PM pollutions were found on workdays and daytime, except organics was dominant at night due to heating activities. Characterization of NPF events were analyzed to provide insight into the behaviors of particle evolution in Lanzhou. Air masses from west are the most polluted and aged clusters, whereas clean air masses mainly originated from the north.