Abstract: Laishui County in Hebei Province is located 90 km southwest to Beijing. In order to understand the local pollution characteristics of particulate matter, individual-particle analysis technique (SEM-EDX) was performed on 7 samples of atmospheric particles collected in 3 typical periods of atmosphere pollution in Laishui County. In total 1506 particles (diameter larger than 0.5 μm) were measured, and the diameter of more than 98% particles was less than 2.5 μm, indicating a characteristic of severe fine particle pollution. The results show that:(1) Carbonaceous particles are the main types of particulate matter and the number detected is over 90%. (2) During the China Military Parade, a non-heating period with strict atmospheric control policies implemented, the spherical carbon-rich particles, which were mainly from daily activities of citizens, had the highest number abundance among all particles. (3) During normal non-heating days, abundance of vehicle-emitted soot aggregates was the highest, which showed the largest contribution of traffic to particle pollution. (4) Abundance of spherical carbon-rich particles was highest during heat-period, while the abundance of S-rich particles was significantly increased, implying the main contribution of coal combustion emission to air pollution. Combined with 48-h analysis of air mass back trajectories in 3 typical periods of atmosphere pollution, it was concluded that the local sources were the main cause of pollutants during periods with low level air pollution, while external and local sources both play an important role during periods with severe air pollution in Laishui County.