Effects of ambient air pollution from municipal solid waste landfill on children's non-specific immunity and respiratory health.

This cross-sectional study investigated the association between air pollutant (AP) and respiratory health of 951 children residing near a municipal solid waste (MSW) landfill in Northern China. Results showed that students in non-exposure areas had significantly higher levels of lysozyme, secretory immunoglobulin A (SIgA), and better lung capacity than students in exposure areas (p < .05). Multiple regression model analysis indicated that lysozyme levels exhibited a consistent negative association with methane (CH4: β = -76.3, 95% CI -105 to -47.7) and sulfuretted hydrogen (H2S: β = -11.7, 95% CI -20.2 to -3.19). In addition, SIgA levels were negatively associated with H2S (β = -68.9, 95% CI -97.9 to -39.9) and ammonia (NH3: β = -30.3, 95% CI -51.7 to -8.96). Among all AP, H2S and sulfur dioxide (SO2) were the most robustly related with reduced lung function. H2S exposure was negatively associated with six lung function indices, 1-s forced expiratory volume (FEV1%), mean forced expiratory flow between 25% and 75% (MMF), maximum voluntary ventilation (MVV), and forced expiratory flow at 25%, 50%, and 75% of the pulmonary volume (FEF25, FEF50, FEF75); and SO2 was negatively associated with FEV1%, MVV, FEF25, FEF50 and FEF75. Our results suggested that AP exposure was negatively associated with more lung function parameters in boys than in girls. In conclusion, our findings suggested that children living adjacent to landfill sites were more likely to have deficient non-specific immunity and impaired lung function.