Spring festival firework activities exacerbate toxic effects of aerosol essential components.

Fireworks cause short-term deterioration of air quality but related health effects remain unclear. This study evaluated the impact of typical fireworks on the chemical composition of atmospheric aerosols and their toxic effects during the Chinese Spring Festival (SF). The concentrations of firework-related water-soluble ions, metallic elements, organic carbon, and elemental carbon during the SF are 1.1-80.7, 1.8-49.1, 3.8-4.9, and 2.0-2.4 times higher than those in background period, respectively. The firework source contributes about 54.6 % to the mass of PM2.5 during the SF period based on positive matrix factorization model. The concentrations of characteristic contaminants associated with fireworks, including Ba, Cr, Ni, benzo(a)pyrene (BaP), and benzo(b)fluoranthene (BbF), exceeded the regional screening level thresholds by 2.2-29.0 times. The toxicity of eye irritation, skin sensitization, drug-induced liver injury, carcinogenicity, and ames dominated the toxicity equivalent quantities of the sixteen polycyclic aromatic hydrocarbons and are 7.5-10.3 times higher than the background levels in D-SF period. The BaP and BbF showed high percentage (60.9 %-63.1 %) among these mainly toxicities due to their relatively high mass concentrations and toxic equivalency factors. Our findings indicate that it is essential to control fireworks display activities to enhance air quality and protect human health.