[Effect of air pollution on respiratory health in school-aged children in the main urban area of Chongqing, China].

OBJECTIVE: To investigate the effect of air pollution on respiratory health in school-aged children in the main urban area of Chongqing, China. METHODS: The main urban area of Chongqing was divided into polluted area and clean area according to the air pollution data shown on the Environmental Protection Agency Website of Chongqing between 2010 and 2015. A cluster sampling method was used to select 695 third- or fourth-grade children from 2 primary schools in the clean or polluted area as study subjects, with 313 children from the clean area and 382 children from the polluted area. Pulmonary function was examined for all children and a standard American epidemiological questionnaire (ATS-DLD-78-C) was used to investigate the prevalence of respiratory diseases and symptoms. RESULTS: Compared with the clean area, the polluted area had significantly higher concentrations of inhalable particles (PM10), fine particulate matter (PM2.5), and nitric oxide (NOX) (P<0.05). The multivariate logistic regression analysis was performed after adjustment for confounding factors, and the results showed that compared with those in the clean area, the children in the polluted area had significantly higher risks of cough (OR=1.644), cough during cold (OR=1.596), expectoration during cold (OR=2.196), persistent expectoration (OR=1.802), and wheezing (OR=2.415). The boys and girls in the clean area had significantly higher forced vital capacity and forced expiratory volume in one second than those in the polluted area (P<0.05). CONCLUSIONS: Air pollution in the main urban area of Chongqing is associated with the increased prevalence of respiratory symptoms in school-aged children and has certain effect on children's pulmonary function.

[Effects of maternal exposure to vehicle exhaust on the reproductive system and DNA methylation in male offspring mice].

OBJECTIVE: To explore the effect of exposure to vehicle exhaust in pregnant mice on the reproductive function and DNA methylation in male offspring mice. METHODS: Twenty pregnant mice were randomized into control group and vehicle exhaust exposure group (n=10) and exposed to routine laboratory condition and to vehicle exhaust for 10 consecutive days (8 h per day) in a tunnel with a heavy traffic, where the concentrations of TSP, PM10, PM2.5, SO2 and NOX and the decibel of noise were measured. The offspring mice were raised till reaching maturity, and the epididymides of the male mice were collected to test the weight coefficients, DNA methylation level, and mRNA levels of Aldh7a1 and Rpe. RESULTS: The body weight and the weight coefficients of the epididymides and testes differed significantly between the exposure group and the control group (P>0.05). The concentrations of TSP, PM2.5, PM10 and NOx and the decibel of noise were significantly higher in the traffic environment and the control environment (P<0.05). Reduced representation bisulphite sequencing (RRBS) and Gene ontology (GO) showed that 58 genes had significantly different methylation levels between the two groups, mostly relating to the process of spermatogenesis (P<0.05). Compared with the control group, Aldh7a1 and Rpe mRNA expressions in the testes were down-regulated significantly in the exposure group (P<0.05). CONCLUSION: Exposure of pregnant mice to vehicle exhaust causes damages of the reproductive function in the male offspring mice.