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11.
Ozone concentrations, flux and potential effect on yield during wheat growth in the Northwest-Shandong Plain of China 总被引:1,自引:0,他引:1
Ozone (O3) concentration and flux (Fo) were measured using the eddy covariance technique over a wheat field in the Northwest-Shandong Plain of China. The O3-induced wheat yield loss was estimated by utilizing O3 exposure-response models. The results showed that: (1) During the growing season (7 March to 7 June, 2012), the minimum (16.1 ppbV) and maximum (53.3 ppbV) mean O3 concentrations occurred at approximately 6:30 and 16:00, respectively. The mean and maximum of all measured O3 concentrations were 31.3 and 128.4 ppbV, respectively. The variation of O3 concentration was mainly affected by solar radiation and temperature. (2) The mean diurnal variation of deposition velocity (Vd) can be divided into four phases, and the maximum occurred at noon (12:00). Averaged Vd during daytime (6:00–18:00) and nighttime (18:00–6:00) were 0.42 and 0.14 cm/sec, respectively. The maximum of measured Vd was about 1.5 cm/sec. The magnitude of Vd was influenced by the wheat growing stage, and its variation was significantly correlated with both global radiation and friction velocity. (3) The maximum mean Fo appeared at 14:00, and the maximum measured Fo was − 33.5 nmol/(m2·sec). Averaged Fo during daytime and nighttime were − 6.9 and − 1.5 nmol/(m2·sec), respectively. (4) Using O3 exposure-response functions obtained from the USA, Europe, and China, the O3-induced wheat yield reduction in the district was estimated as 12.9% on average (5.5%–23.3%). Large uncertainties were related to the statistical methods and environmental conditions involved in deriving the exposure-response functions. 相似文献
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This report summarizes the results of two studies of electricity supply for Europe (EU), the Middle East (ME) and North Africa
(NA) up to the year 2050. It shows that a transition to competitive, secure and sustainable supply of electricity and water
is possible using renewable energy sources, efficiency gains and fossil fuel backup for balancing power. A strong cooperation
between the EU and MENA for the market introduction of renewable energy and the interconnection of the electricity grids by
high-voltage direct-current transmission are keys to the success and survival of the whole region. However, the necessary
measures will take at least two decades to become effective. Therefore, adequate policy and economic frameworks for their
realization must be introduced immediately. The importance of sustainable energy for the security of freshwater supplies in
MENA is also described.
相似文献
Hans Müller-SteinhagenEmail: |
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Gerhard Scherer Thomas Ruppert Helmut Daube Irmtrud Kossien Kirsten Riedel Anthony R. Tricker Franz Adlkofer 《Environment international》1995,21(6)
The concentrations of environmental tobacco smoke (ETS) constituents including benzene were measured in the living rooms of 10 nonsmoking households and 20 households with at least one smoker situated in the city and suburbs of Munich. In the city, the median benzene levels during the evening, when all household members were at home, were 8.1 and 10.4 μg/m3 in nonsmoking and smoking homes, respectively. The corresponding levels of 3.5 and 4.6 μg/m3 were considerably lower in the suburbs. Median time-integrated 1-week benzene concentrations in the city were 10.6 μg/m3 in nonsmoking homes and 13.1 μg/m3 in smoking homes. In the suburbs, the corresponding values were 3.2 and 5.6 μg/m3. While the benzene concentrations in nonsmoking homes located in the city were significantly higher (p < 0.05) than in suburban nonsmoking households, no difference was found between smoking and nonsmoking households located either in the city or in the suburbs. Individual exposures to benzene and to specific markers for tobacco smoke of all household members (82 nonsmokers and 32 smokers) were determined by questionnaire, personal monitoring, and biomonitoring. Within the city, the benzene exposure determined by personal samplers was 11.8 μg/m3 for nonsmokers living in nonsmoking homes and 13.3 μg/m3 for nonsmokers in smoking homes. The corresponding values for nonsmokers living in the suburbs were 5.9 and 6.9 μg/m3, respectively. Neither difference was statistically significant. Nonsmokers living in nonsmoking households in the city had significantly higher exposure to benzene compared to their counterparts living in the suburbs (personal samplers: 11.8 vs 5.9 μg/m3, p < 0.001; benzene in exhalate: 2.4 vs. 1.1 μg/m3, p < 0.05; trans,trans-muconic acid excretion in urine: 92 vs. 54 μg/g creatinine, p < 0.05). Nonsmokers from all households with smokers were significantly more exposed to benzene than nonsmokers living in the nonsmoking households (personal samplers: 13.2 vs. 7.0 μg/m3, p < 0.05; benzene in exhalate: 2.6 vs. 1.8 μg/m3, p < 0.01; trans,trans-muconic acid excretion in urine: 73 vs. 62 μg/g creatinine), but the contribution of ETS to the total benzene exposure was relatively low compared to that from other sources. Analysis of variance showed that at most 15% of the benzene exposure of nonsmokers living in smoking homes was attributable to ETS. For nonsmokers living in nonsmoking households benzene exposure from ETS was insignificant. 相似文献
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Franz Wolf 《Die Naturwissenschaften》1956,43(18):415-417
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