Influence of fireworks emission on aerosol aging process at lower troposphere and associated health risks in an urban region of eastern central India.

To study the influence of fireworks in atmospheric aerosols and their effect on health during the extreme firework days, fireworks tracer metals and carbonaceous species in size-distributed aerosols in the lower troposphere at Raipur in eastern central India were investigated during the 2018 Deepawali festival. Aerosol samples were collected, before Deepawali period (BDP, n = 5), during Deepawali period (DDP, n = 5) and after Deepawali period (ADP, n = 5). Bimodal size-distribution with intense fine mode peak was found for Na during DDP. Bimodal distribution with fine mode intense peak was found for K during DDP. The bimodal size distribution of K was found common for other events because of biomass burning emissions, whereas high intense peak during DDP indicated mixed sources from biomass burning and fireworks. During DDP, K and Ca were well correlated (r = 0.93) together. Strong metal-metal correlations were found between the following pairs, Zn-Fe, Cu-Fe and Cu-Ca, which indicated the similar firecrackers burning source. The atmospheric aging of aerosols was also found significantly high during fireworks days. Aging of aerosols were higher because of heterogeneous reactions of SO and NO on aerosols directly emitted from fireworks. The observed high values of inhalation dose of elemental carbon during DDP period imposed higher risk of respiratory diseases. This study has provided carbonaceous fractions composition data as a tool to detect the aging processes of fireworks in ultra-fine, fine and coarse mode particles during the extreme firework days. Inhalation doses were calculated to establish potential influence on human health.