Characterizing the composition and evolution of firework-related components in air aerosols during the Spring Festival.

To examine the impacts of fireworks, size-resolved PM samples were collected using a single-particle aerosol mass spectrometer before, during and after the Spring Festival in a megacity in Chengdu, China. Chemical composition and atmospheric behavior of urban particles were studied. Ten major single particle types were resolved with ART-2a algorithm including elemental and organic carbon (ECOC), EC, OC, levoglucosan (LEV), high molecular weight organic molecules (HOM), hard metal (HM), K rich, Na rich and SiO. The average OC/EC ratios decreased in the order AY (4.7) > overall (4.1) > NY (4.0) > BY period (3.6), indicating that many organic pollutants had been generated after the Spring Festival. The concentrations of many species exhibited an increasing trend during the firework period, and the SOR and NOR showed a strong increase in NY period. SOR and NOR had a slight positive relationship with fireworks activity but no obvious relationship with temperature.