Long-term effects of emission reduction measures on PM_2.5 sources and children's lung function in Jinan, China

Many studies have reported the damaging effect of PM_2.5 on the lung function of school-age children, but the potential impact of different PM_2.5 sources remains unclear. This study analyzed the composition of PM_2.5 at a sampling site in Jinan City between 2014 and 2020. Coinciding with the implementation of the environmental protection policies in Jinan, the study time was segmented into three distinct periods. PM_2.5 and its components (such as metals and polycyclic aromatic hydrocarbons) gradually decreased across these periods. The results of the Positive Matrix Factorization (PMF) showed that the concentrations of PM_2.5 were reduced to varying degrees for different sources. The generalized linear model, after adjustment, found that increased industrial emissions were associated with decreased FVC (OR: 0.92, 95%CI: 0.87-0.98) and FEV1 (OR: 0.91, 95%CI: 0.86-0.96) in girls during Period 1. In Period 2, biomass burning and road dust were associated with a decrease in FVC (OR: 0.91, 95%CI: 0.84-0.99) and FEV1 (OR 0.92, 95%CI: 0.85-0.99) for boys, and in the same period, the reductions in FVC (OR: 0.90, 95%CI: 0.83-0.97), FEV1 (OR: 0.91, 95%CI: 0.85-0.97) and PEF (OR: 0.77, 95% CI: 0.68-0.90) in girls were associated with gasoline combustion. No source was found to be associated with a decrease in lung function among school-age children in Period 3 when air quality improved substantially. The results suggest that the environmental protection policy in Jinan City has controlled PM_2.5 pollution levels to some extent, which may have improved children's lung function.