RESUMEN

Evidence on the link of long-term exposure to ozone (O3) with childhood asthma, rhinitis, conjunctivitis and eczema is inconclusive. We did a population-based cross-sectional survey, including 177,888 children from 173 primary and middle schools in 14 Chinese cities. A satellite-based spatiotemporal model was employed to assess four-year average O3 exposure at both residential and school locations. Information on asthma, allergic rhinitis, eczema and conjunctivitis was collected by a standard questionnaire developed by the American Thoracic Society. We used generalized non-linear and linear mixed models to test the associations. We observed linear exposure-response associations between O3 and all outcomes. The odds ratios of doctor-diagnosed asthma, rhinitis, eczema, and conjunctivitis associated with per interquartile increment in home-school O3 concentration were 1.31 (95 % confidence interval [CI]: 1.28, 1.34), 1.25 (95 %CI: 1.23, 1.28), 1.19 (95 %CI: 1.16, 1.21), and 1.28 (95 %CI: 1.21, 1.34), respectively. Similar associations were observed for asthma-related outcomes including current asthma, wheeze, current wheeze, persistent phlegm, and persistent cough. Moreover, stronger associations were observed among children who were aged > 12 years, physically inactive, and exposed to higher temperature. In conclusion, long-term O3 exposure was associated with higher risks of asthma, allergic rhinitis, conjunctivitis and eczema in children.

Asunto(s)

Contaminantes Atmosféricos , Asma , Ciudades , Conjuntivitis , Eccema , Ozono , Rinitis , Humanos , Ozono/análisis , Ozono/toxicidad , Niño , China/epidemiología , Asma/epidemiología , Asma/inducido químicamente , Eccema/epidemiología , Eccema/inducido químicamente , Masculino , Femenino , Rinitis/epidemiología , Rinitis/inducido químicamente , Contaminantes Atmosféricos/toxicidad , Contaminantes Atmosféricos/análisis , Conjuntivitis/inducido químicamente , Conjuntivitis/epidemiología , Estudios Transversales , Exposición a Riesgos Ambientales/efectos adversos , Adolescente

RESUMEN

Aiming to expand the utilization of porous silicate minerals in the remediation of heavy metal contaminated soil,the mesoporous material SBA-15 was successfully synthesized by using sodium silicate as silica source in this study.And the obtained SBA-15 samples were characterized by TEM,X-ray diffraction,N2 adsorption-desorption and FTIR.Furthermore,characterization of Cd (Ⅱ) adsorption and sealing performance onto SBA-15 were evaluated through batch experiment,and the remediation potential of Cd (Ⅱ) contaminated soil was investigated by brassica planting in a pot experiment.The results showed that SBA-15 had the mesoporous structure with surface area of 507.3 m2·g-1 and pore size of 7.38 nm.The maximum Cd (Ⅱ) adsorption capacity was 76.43 mg·g-1 at pH above 7.0 with the adsorption isotherm fitting the Langmuir model in the solution of 100 mg·L-1 Cd (Ⅱ).The increase in ionic strength reduced the Cd (Ⅱ) adsorption capacity.The Cd (Ⅱ) loaded SBA-15 could be regenerated with 0.1 mol·L-1 HNO3,while Cd (Ⅱ) could be strongly sealed in the pore structure after introduction of sodium silicate into the system.The pot experiment proved that the addition of SBA-15(4.5 g·kg-1) into Cd-contaminated soil could reduce Cd (Ⅱ) availability,enhance the transformation of soluble and exchangeable Cd (Ⅱ) fractions into carbonate and Fe-Mn oxides bounded forms,inhibit the Cd (Ⅱ) accumulation in the plant tissue and improve the brassica growth.Based on these results,it can be concluded that combination of the SBA-15 particle with sodium silicate has great potential to remediate Cd (Ⅱ) contaminated soil through adsorption and sealing properties.