[Source Apportionment and Pollution Characteristics of PM2.5 During the Two Heavy Pollution Episodes in the Winter of 2016 in a Typical Logistics City].

of Linyi city in the winter. Compared with the average concentration over the whole sampling period, the contribution of secondary particles during the two pollution episodes was significantly increased. This indicates that the formation and accumulation of secondary particulate matter under static and humid meteorological conditions were the main influencing factors during the heavy pollution episodes.