ABSTRACT
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.
Subject(s)
Air Pollutants , Asthma , Cities , Conjunctivitis , Eczema , Ozone , Rhinitis , Humans , Ozone/analysis , Ozone/toxicity , Child , China/epidemiology , Asthma/epidemiology , Asthma/chemically induced , Eczema/epidemiology , Eczema/chemically induced , Male , Female , Rhinitis/epidemiology , Rhinitis/chemically induced , Air Pollutants/toxicity , Air Pollutants/analysis , Conjunctivitis/chemically induced , Conjunctivitis/epidemiology , Cross-Sectional Studies , Environmental Exposure/adverse effects , AdolescentABSTRACT
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 (â ¡) adsorption and sealing performance onto SBA-15 were evaluated through batch experiment,and the remediation potential of Cd (â ¡) 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 (â ¡) 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 (â ¡).The increase in ionic strength reduced the Cd (â ¡) adsorption capacity.The Cd (â ¡) loaded SBA-15 could be regenerated with 0.1 mol·L-1 HNO3,while Cd (â ¡) 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 (â ¡) availability,enhance the transformation of soluble and exchangeable Cd (â ¡) fractions into carbonate and Fe-Mn oxides bounded forms,inhibit the Cd (â ¡) 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 (â ¡) contaminated soil through adsorption and sealing properties.