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Fine particulate matter is associated with adverse health effects, but exactly which characteristics of PM 2.5 are responsible for this is still widely debated. We evaluated seasonal dynamics of the composition and chemical characteristics of PM 2.5 in Zhuhai, China. PM 2.5 characteristics at five selected sites within Zhuhai city were analyzed. Sampling began on January 10, 2015, and was conducted for 1 year. The ambient mass concentration, carbon content (organic and elemental carbon, OC and EC), level of inorganic ions, and major chemical composition of PM 2.5 were also determined. Average concentrations of PM 2.5 were lower than the National Ambient Air Quality Standard (NAAQS) 24-h average of 65 μg/m 3 . The daily PM 2.5 concentration in Zhuhai city exhibited clear seasonal dynamics, with higher daily PM 2.5 concentrations in autumn and winter than in spring and summer. Carbon species (OC and EC) and water-soluble ions were the primary components of the PM 2.5 fraction of particles. Apart from OC and EC, chemical species in PM 2.5 were mainly composed of NH 4 + and SO 4 2- . There was a marked difference between the summer and winter periods: the concentrations of OC and EC in winter were roughly 3.4 and 4.0 times than those in summer, while NH 4 + , SO 4 2- , NO 3 - , and Na + were 3.2, 4.5, 28.0, and 5.7 times higher in winter than those in summer, respectively. The results of chemical analysis were consistent with three sources dominating PM 2.5 : coal combustion, biomass burning, and vehicle exhaust; road dust and construction; and from reaction of HCl and HNO 3 with NH 3 to form NH 4 Cl and NH 4 NO 3 . However, additional work is needed to improve the mass balance and to obtain the source profiles necessary to use these data for source apportionment.