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Erisman J. W. Hensen A. Fowler D. Flechard C. R. Grüner A. Spindler G. Duyzer J. H. Weststrate H. Römer F. Vonk A. W. Jaarsveld H. v. 《Water, Air, & Soil Pollution: Focus》2001,1(5-6):17-27
Between 1993 and 1999 two EU funded projects wereexecuted aimed at (i) the development of drydeposition monitoring methods for core sites andlarge scale application, (ii) the installation andrunning of three core sites in Europe and (iii) the improvement and validation of models used forregional application. This article provides anoverview of the development of depositionmonitoring stations and the main results of thethree core sites, which were operated between1995 and 1998. Furthermore, the results of thedevelopment of a low cost monitoring system arepresented. Continuous measurements were made ofboth wet and dry deposition of sulphur andnitrogen components and base cations. The 4 yearsof data show a decrease in sulphur loads and notrend for the other components. It is shown thatthe surface affinities for sulphur depositionalso changed during the years, underpinning theneed for dry deposition monitoring. A conditionaltime average gradient system was successfullydeveloped and tested and provides a good meansfor low cost monitoring of dry deposition fluxes.The costs can be reduced by a factor of 3–4 without losing the accuracy of the annual average gas fluxes. 相似文献
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Gregory M. Clark David K. Mueller M. Alisa Mast 《Journal of the American Water Resources Association》2000,36(4):849-860
ABSTRACT: Data from 85 sites across the United States were used to estimate concentrations and yields of selected nutrients in streams draining relatively undeveloped basins. Flow‐weighted concentrations during 1990–1995 were generally low with median basin concentrations of 0.020, 0.087, 0.26, 0.010, and 0.022 milligrams per liter (mg/L) for ammonia as N, nitrate as N, total nitrogen, orthophosphate as P, and total phosphorus, respectively. The flow‐weighted concentration of nitrate exceeded 0.6 mg/L in only three basins. Total nitrogen exceeded 1 mg/L in only four basins, and total phosphorus exceeded 0.1 mg/L in only four basins. The median annual basin yield of ammonia as N, nitrate as N, total nitrogen, orthophosphate as P, and total phosphorus was 8.1, 26, 86, 2.8, and 8.5 kilograms per square kilometer, respectively. Concentrations and yields of nitrate tended to be highest in northeastern and mid‐Atlantic coastal states and correlated well with areas of high atmospheric nitrogen deposition. Concentrations and yields of total nitrogen were highest in the southeastern part of the nation and in parts of the upper Midwest. In the northeast, nitrate was generally the predominant form of nitrogen, and in the southeast and parts of the upper Midwest, organic nitrogen was the dominant form. Concentrations of total phosphorus were generally highest in the Rocky Mountain and Central Plain states. 相似文献
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使用GCIECD(气相色谱/电子捕获检测器)及毛细色谱柱定量分析粤港地区气溶胶和餐厅烟尘中有机氯农药的组成和分布特征,并分析其主要来源研究表明,从研究区大气环境中的气溶胶样品及餐厅烟尘颗粒物中,检出12种有机氯农药.其中6种DDT(滴滴涕)及其代谢物,3种BHC(六六六)和其它3种含氯农药,浓度范围在0.20~60.78pg/m3.靠近农田和果园的气溶胶及餐厅烟尘颗粒物中4,4'-DDT和2,4'-DDT浓度较高,说明大气环境中的DDT不仅来源于农药施撒过程和农田表层土壤,而且还来源于动物脂肪高温裂解的释放。 相似文献
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上甸子本底站地面臭氧变化特征及影响因素 总被引:20,自引:3,他引:17
利用TE Model 49C型臭氧监测仪,于2004年1月1日-12月31日,在上甸子本底站进行了地面φ(O3)的连续在线监测.分析了全年φ(O3)的变化特征及其与同期气象要素的相关关系,并对φ(O3)高值日的个例分析进行了验证.结果表明,上甸子本底站地面φ(O3)具有明显的季节变化和日变化规律,并且与同期的气象条件密切相关.主要特征:①夏初φ(O3)较高,6月的平均值达到最高,小时平均最大值可达129.7 μL/m3;而冬季φ(O3)较低,12月的平均值达到最低,小时平均最大值仅为32.7 μL/m3.②日变化趋势较为明显,在4:00-7:00出现最低值,在15:00-18:00出现最高值,变化幅度为夏季最大、冬季较小.③气温与φ(O3)呈显著正相关,夏季相对湿度与φ(O3)呈显著负相关,风向和辐射强度也与φ(O3)及其变化规律呈显著相关关系. 相似文献