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Background: Allergic rhinitis (AR) is a common chronic inflammatory disease with bothersome symptoms. However, the effect of air pollution on the prevalence of AR in children is controversial. Objective: This study aimed to investigate the association between air pollution and the prevalence of AR in Chinese children. Methods: This study, in China, included 160,356 students ages 0-18 years who completed a questionnaire about the accuracy of the International Study of Asthma and Allergies in Childhood (ISAAC). The effect of different air pollutants on the prevalence rate were evaluated by meta-analysis. Also, it evaluated the effect of different air pollutants on the prevalence rate. Results: The differences in the effects of sulfur dioxide (SO2) exposure (combined odds ratio [ORcombined] 1.03 [95% confidence interval {CI}, 1.01-1.05]; p = 0.010) and nitrogen dioxide (NO2) exposure (ORcombined 1.11 [95% CI, 1.05-1.18]; p = 0.0006) on the risk of childhood AR was statistically significant. The effect of particulate matter with aerodynamic diameter of <10 mm (PM10) exposure on the risk of childhood AR was statistically significant (ORcombined 1.02 [95% CI, 1.01-1.03]; p < 0.001), the effect of particulate matter with aerodynamic diameter of <2.5 mm (PM2.5) exposure on the risk of childhood AR was statistically significant (ORcombined 1.15 [95% CI, 1.03-1.29]; p = 0.02), and the effect of ozone exposure on the risk of childhood AR was not statistically significant (ORcombined 0.98 [95% CI, 0.67-1.41]; p = 0.13). Conclusion: NO2, SO2, PM2.5, and PM10 were associated with the prevalence of AR in Chinese children. PM2.5 had the highest correlation with AR prevalence. [ABSTRACT FROM AUTHOR]

Biological soil crusts (BSCs) in arid region provide critical ecosystem services. However, most previous studies on BSC-plant topic have had a narrow spatiotemporal and taxonomic focus, so context dependency concerning exotic plant responses to BSCs remains poorly understood. In this study, using a series of manipulative experiments under greenhouse conditions, we investigated the influence of BSCs in the Tengger Desert in northern China on seed germination and seedling growth of an exotic grass species, Stipa glareosa P. Smirn., with or without two native plants species, Eragrostis poaeoides Beauv. and Artemisia capillaris Thunb., both of whose ontogeny differs from that of the exotic species. BSC treatments included intact crusts, disturbed crusts, and bare soil. Compared to bare soil, the presence of BSCs reduced the germination of E. poaeoides and A. capillaris by 78% and 74%, respectively. For the exotic species, BSCs reduced the germination percentage by as much as 90%. With gradual increases in soil nutrients such as organic carbon, available phosphorus, and available nitrogen, the shoot biomass of the three plants increased along the sequence from bare soil to lichens and mosses. Shoot biomass of the two native plant species was reduced by the exotic species S. glareosa. The percent germination and shoot biomass of S. glareosa on the disturbed crusts were greater than those on the intact crusts and bare soils. Overall, the presence of BSCs on stabilized sand dunes can reduce the germination of these three plant species, but compared with native plant species, BSCs have a stronger inhibitory effect on the seed germination of the exotic plant species. However, the disturbance may weaken the inhibition of the seed germination of the exotic grass S. glareosa and may provide more nutrients for the exotic grass S. glareosa to establish a revegetation region. We concluded that compared with the absence of BSCs, BSCs in this desert ecosystem can provide more nutrients and a suitable environment for native vascular plants and exert an inhibitory effect on the exotic plants. [ABSTRACT FROM AUTHOR]

Background. Current and future changes in rainfall amount and frequency may particularly impact annual plants in desert ecosystems. The winter annual Echinops gmelinii Turcz. is widely distributed in the desert habitats of northern China and is a dominant pioneer annual plant following sand stabilization in the Tengger Desert. This species plays a vital role in dune stabilization during spring and early summer, when wind erosion is the most severe and frequent. However, seedling emergence and regeneration in sandy soil are mainly determined by rainfall patterns. Therefore, understanding the life history response of this species to rainfall variation is necessary for understanding the change of population dynamics under the future climate change. Methods. A field simulation rainfall pot experiment using rainout shelter was conducted that included five amounts and five frequencies of rainfall based on historical and predicted values to monitor the life history responses of E. gmelinii in a near-natural habitat. Results. We found that rainfall amount and frequency significantly affected seedling survival, growth and reproduction. The plant height, biomass, capitula number, seed number, seed mass and reproductive effort, but not the root/shoot ratio, significantly increased with increasing rainfall. Further, these traits exhibited the greatest response to low-frequency and larger rainfall events, especially the optimal rainfall frequency of 10-day intervals. Offspring seed germination showed increasing trends with decreasing rainfall, suggesting that the maternal effects may have occurred. Conclusions. Our study shows that the plasticity in growth and reproduction of E. gmelinii in response to rainfall variations may help it to gain dominance in the harsh and unpredictable desert environment. Furthermore, population development of this winter annual species should be promoted under the likely future scenarios of large rainfall events and increasing cool-season precipitation in temperate desert. [ABSTRACT FROM AUTHOR]

Despite evidence from experimental grasslands that plant diversity increases biomass production and soil organic carbon (SOC) storage, it remains unclear whether this is true in natural ecosystems, especially under climatic variations and human disturbances. Based on field observations from 6,098 forest, shrubland, and grassland sites across China and predictions from an integrative model combining multiple theories, we systematically examined the direct effects of climate, soils, and human impacts on SOC storage versus the indirect effects mediated by species richness (SR), aboveground net primary productivity (ANPP), and belowground biomass (BB). We found that favorable climates (high temperature and precipitation) had a consistent negative effect on SOC storage in forests and shrublands, but not in grasslands. Climate favorability, particularly high precipitation, was associated with both higher SR and higher BB, which had consistent positive effects on SOC storage, thus offsetting the direct negative effect of favorable climate on SOC. The indirect effects of climate on SOC storage depended on the relationships of SR with ANPP and BB, which were consistently positive in all biome types. In addition, human disturbance and soil pH had both direct and indirect effects on SOC storage, with the indirect effects mediated by changes in SR, ANPP, and BB. High soil pH had a consistently negative effect on SOC storage. Our findings have important implications for improving global carbon cycling models and ecosystem management: Maintaining high levels of diversity can enhance soil carbon sequestration and help sustain the benefits of plant diversity and productivity. [ABSTRACT FROM AUTHOR]

A USEPA, procedure, ISCLT3 (Industrial Source Complex Long-Term), was applied to model the spatial distribution of polycyclic aromatic hydrocarbons (PAHs) emitted from various sources including coal, petroleum, natural gas, and biomass into the atmosphere of Tianjin, China. Benzo[a]-pyrene equivalent concentrations (BaPeq) were calculated for risk assessment. Model results were provisionally validated for concentrations and profiles based on the observed data at two monitoring stations. The dominant emission sources in the area were domestic coal combustion, coke production, and biomass burning. Mainly because of the difference in the emission heights, the contributions of various sources to the average concentrations at receptors differ from proportions emitted. The shares of domestic coal increased from ~43% at the sources to 56% at the receptors, while the contributions of coking industry decreased from ~23% at the sources to 7% at the receptors. The spatial distributions of gaseous and particulate PAHs were similar, with higher concentrations occurring within urban districts because of domestic coal combustion. With relatively smaller contributions, the other minor sources had limited influences on the overall spatial distribution. The calculated average BaPeq value in air was 2.54 ± 2.87 ng/m³ on an annual basis. Although only 2.3% of the area in Tianjin exceeded the national standard of 10 ng/m³, 41% of the entire population lives within this area. [ABSTRACT FROM AUTHOR]

Shapotou Desert Research Station is located at the southeast edge of Tengger Desert in China. Shapotou sand dunes have been vegetated to stabilize them. The vegetated dunes have been completely covered by a natural crust. Rain infiltration was reduced by 36 % to 74 % on the crusted site while there was no reduction of rain infiltration on the sandy site. The infiltration rate was positively correlated with total rainfall and negatively correlated with rain intensity. Runoff on the crusted site provided water for vegetation growth in the hollows between sand dunes. The crust significantly impeded increased soil moisture. To increase soil moisture in the surface 40 cm layer, rainfall had to be above 8.5 mm on the slopes of sand dunes on the crust site, and increased with rain intensity. In the Shapotou area, the amount of rainfall that vegetation on slopes of sand dunes could utilize, was reduced to about 40 mm per year by the crust, although the mean annual precipitation was approx imately 180 mm. It is expected that vegetation cover will continuously degrade in the future. To maintain vegetative cover adequate to stabilize the active sand dune, it was necessary to break part of the crust at slope of sand dune. [ABSTRACT FROM AUTHOR]

The spatial and temporal patterns of pedogenesis on stabilized dunes at Shapotou, northwestern China, were studied on the time sequences of 0, 18, 35 and 43 years. The spatial pattern of soil formation was estimated by measuring the thickness of accumulated sand fractions on the stabilized dune surface and by analyzing the characteristics and properties of soil. The results showed that the environment of soil formation and circulation of soil material were influenced in the processes of shifting-sand fixation, and the mean soil particle size changed from >0.2 to <0.08 mm in 0–20 cm soil depth with the succession from cultivated plants to natural vegetation. The capacity of available soil water increased fivefold. Deep infiltration of water in soil no longer occurred due to the increase in soil water capacity and the change of redistribution of soil water in profiles. Soil microorganisms evolved from simple to complex. Interaction of these processes obviously brought about accumulation of soil fertility, evolution of soil profiles and development of the profiles towards aripsamments. The difference of micro-topography is closely related to redistribution of material and energy in soil formation. [Copyright &y& Elsevier]

Abstract: Renewable energy is the inevitable choice for sustainable economic growth, for the harmonious coexistence of human and environment as well as for the sustainable development. Government support is the key and initial power for developing renewable energy. In this article, an overall review has been conducted on renewable energy development policy (including laws and regulations, economic encouragement, technical research and development, industrialized support and government model projects, etc.) in China. On this basis, a systematic analysis has been conducted on the disadvantages of renewable energy development policy. On the point of long-term effective system for renewable energy development, a series of policy advice has been offered, such as strengthening the policy coordination, enhancing regional policy innovation, echoing with clean development mechanism, implementing process management, constructing market investment and financing system. It is expected that the above advices could be helpful to ever-improvement of renewable energy development policy. [Copyright &y& Elsevier]