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. 2020 Jun 5;739:140000. doi: 10.1016/j.scitotenv.2020.140000

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Fig. 2 — Source profiles of biomass burning (BB), coal combustion (CC), firework burning (FW), industrial processes (IP), road dust (RD), secondary inorganic aerosol (SIA), and vehicle emissions (VE) for 01/23 00:00– 02/22 23:00 in 2019 (left panel) and 2020 (right panel) derived from PMF model. The boxplots are constructed according to the bootstrap results (n = 100).