Characterization of lead-containing aerosol particles in Xiamen during and after Spring Festival by single-particle aerosol mass spectrometry.

To comparatively analyze lead (Pb)-containing particles during and after the Chinese Spring Festival (SF), real-time single-particle aerosol mass spectrometry (SPAMS) was conducted in Xiamen during February 9-19 and March 4-14, 2013. Pb-containing particles were found in 2.4% and 5.3% of the total particle numbers during and after SF, respectively. Based on the SPAMS mass spectral results, the Pb-containing particles were classified into three major types and 11 subtypes: Pb-rich particles comprising Pb-nitrate, Pb-sulfate and Pb-chloride; K-rich particles comprising K-nitrate, K-sulfate, K-metal, K-carbonaceous, K-phosphate, and K-chloride; and metal particles including Fe-rich and Mn-nitrate particles. During SF, lower contributions of Pb-containing particles were due to the effect of the SF holiday. Firework emissions contributed little to the Pb-containing particles. K-rich particles were a major contribution to Pb-containing particles during SF, accounting for approximately 70% of the total number of Pb-containing particles. After SF, significantly increased Pb-containing particles were observed, coincided with NO2 and SO2 , due to increased industrial activities and other anthropogenic activities, and Pb-rich particles increased to approximately 50.3% of the total number of Pb-containing particles. Local industrial emissions and the stagnant meteorological conditions resulted in the higher concentrations of Pb-containing particles in the early morning after SF, especially Pb-nitrate particles. This study provides data on the in-situ monitoring of Pb emissions during and after SF and could be helpful for the mitigation of Pb pollution.