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71.
利用区域空气质量模式Models-3/CMAQ对我国2010年的氮沉降特征进行了模拟分析.结果表明,2010年我国氮沉降总量约为7.6′ 103Gg,化学组成上以NHx-N(包括NH3、NH4+中的氮)沉降为主,平均占到2/3以上.夏季氮沉降量最高,冬季最低.干沉降为氮沉降的主要途径(约占62%),主要为气态含氮污染物的贡献,湿沉降的氮则主要来自颗粒态的铵盐和硝酸盐.我国氮沉降的空间分布具有东高西低、地区间差异显著的特征,高沉降通量区域主要集中在华北平原、四川盆地、华中的中南部、两广以及东北部分地区.加强对氨排放的管理和控制,同时重视东部沿海的发达地区的氮氧化物排放,对减少氮沉降具有重要意义. 相似文献
72.
73.
为研究太原地区的大气氮湿沉降时空变化规律,于2016年1月~2017年12月采用雨量器对太原市市中、近郊和远郊三地大气氮湿沉降进行了为期2年的监测。得到市中、近郊、远郊的NO3--N平均浓度为12.9、18.4、1.3 mg/L,NH4+-N平均浓度分别为3.6、2.3、1.6 mg/L。季节变化上看,NH4+-N浓度值四季相对平均,春夏季稍高,而NO3--N浓度变化较大且冬春季浓度值较高。三个采样点大气氮湿沉降量(无机氮)年均沉降量分别为40.0、48.0、14.2 kg/hm2,以近郊的沉降量最高。市中、近郊、远郊的NH4+-N沉降量分别为9.0、5.0、8.2 kg/hm2,占总无机氮湿沉降量的比重分别为22%、11%、57%,NO3--N沉降量分别是31.0、43.0、6.0 kg/hm2,占总无机氮湿沉降量的比重分别为78%、89%、43%。从上可知城市降水中主要以NO3--N沉降为主,农村则以NH4+-N沉降为主。结合市中、近郊、远郊NH4+-N/NO3--N浓度比值分别为0.54、0.30、1.31,充分表明市中和近郊大气氮湿沉降主要来自工业和交通运输源,远郊则来自农业源。另外,市中、近郊月氮湿沉降量与降雨量差异不显著,远郊则达到极显著水平,说明影响市区两点氮湿沉降的因素较为复杂。由以上数据看出市中和近郊氮污染情况比较严重,应根据各自沉降特点予以控制。 相似文献
74.
华南地区高山酸沉降化学研究 总被引:16,自引:1,他引:16
1987—1989年春季,在华南地区衡山、狮子山、苗儿山和白云山观测到华南高山降水酸化,各测点降水pH<5.6的频率大于68%,平均pH值在3.56—4.85之间,分析了高山降水的化学特征,及其与高山的地理环境等因素的关系.结果表明,高山雨水与高空云水有相似性,狮子山和白云山的云雾水主要属地形云,受局地源的影响更为严重,化学性质更接近于地面雨水. 相似文献
75.
Martin Braniš 《Water, Air, & Soil Pollution: Focus》2008,8(1):49-60
To assess the effect of changes in traffic density and fuels used for heating at the beginning of the 1990s, 1992–2005 monthly
averages of PM10, SO2, NO2, NO, CO and O3 from Prague, the Czech capital, were analyzed together with long term trends in emissions of major pollutants, fuel consumption
and number of vehicles registered in Prague. The data from all monitoring stations were retrieved from the database of the
state automated monitoring system. Correlation coefficients between ambient monthly averaged temperature and all pollutants
of concern showed distinct seasonal trends. The results showed that while SO2 and to some extent also CO concentrations dropped namely in the first half of the analyzed period (1992–1997) as a result
decreased fossil fuel consumption for local heating, the behaviour of other pollutant concentrations followed a different
pattern. PM10 concentrations decreased during the beginning of the 1990s but showed a sign of increase after 2000. Concentrations of ozone
and NO2 did not reveal any significant change throughout the whole studied period. It can be concluded that during the studied period
traditional urban sources of pollution, such as coal and oil combustion, lost their importance but were simultaneously substituted
by pollutants from automotive transport (namely PM and NO2) making the problem of air quality even worse. 相似文献
76.
酸沉降物对土壤化学性质的影响 总被引:1,自引:0,他引:1
本文综述了酸沉降物对土壤酸化、营养物质的淋溶、重金属的活化、矿物分解等化学性质的影响,以及阻止酸雨危害土壤的化学方法。 相似文献
77.
Observations of Atmospheric Nitrogen and Phosphorus Deposition During the Period of Algal Bloom Formation in Northern Lake Taihu,China 总被引:4,自引:1,他引:4
Cyanobacterial blooms in Lake Taihu occurred at the end of April 2007 and had crucial impacts on the livelihood of millions
of people living there. Excessive nutrients may promote bloom formation. Atmospheric nitrogen (N) and phosphorus (P) deposition
appears to play an important role in algal bloom formation. Bulk deposition and rain water samples were collected respectively
from May 1 to November 30, 2007, the period of optimal algal growth, to measure the bulk atmospheric deposition rate, wet
deposition rate, and dry deposition rate for total nitrogen (TN; i.e., all species of nitrogen), and total phosphorus (TP;
i.e., all species of phosphorus), in northern Lake Taihu, China. The trends of the bulk atmospheric deposition rate for TN
and the wet deposition rate for TN showed double peaks during the observation period and distinct influence with plum rains
and typhoons. Meanwhile, monthly bulk atmospheric deposition rates for TP showed little influence of annual precipitation.
However, excessive rain may lead to high atmospheric N and P deposition rates. In bulk deposition samples, the average percentage
of total dissolved nitrogen accounting for TN was 91.2% and changed little with time. However, the average percentage of total
dissolved phosphorus accounting for TP was 65.6% and changed substantially with time. Annual bulk atmospheric deposition rates
of TN and TP during 2007 in Lake Taihu were estimated to be 2,976 and 84 kg km−2 a−1, respectively. The results showed decreases of 34.4% and 78.7%, respectively, compared to 2002–2003. Annual bulk deposition
load of TN for Lake Taihu was estimated at 6,958 t a−1 in 2007 including 4,642 t a−1 of wet deposition, lower than the values obtained in 2002–2003. This may be due to measures taken to save energy and emission
control regulations in the Yangtze River Delta. Nevertheless, high atmospheric N and P deposition loads helped support cyanobacterial
blooms in northern Lake Taihu during summer and autumn, the period of favorable algal growth. 相似文献
78.
David Fowler Rognvald Smith Jennifer Muller John Neil Cape Mark Sutton Jan Willem Erisman Hilde Fagerli 《Water, Air, & Soil Pollution: Focus》2007,7(1-3):41-47
Emissions of sulphur and oxidized nitrogen compounds in Europe have been reduced following a series of control measures during
the last two decades. These changes have taken place during a period in which the primary gases and the wet deposition throughout
Europe were extensively monitored. Since the end of the 1970s, for example land based sulphur emissions declined by between
90 and 70% depending on the region. Over the same period the total deposition of sulphur and its partitioning into wet and
dry deposition have declined, but the spatial pattern in the reduction in deposition differs from that of emission and has
changed with time. Such non-linearities in the emission-deposition relationship are important to understand as they complicate
the process of assessing the effects of emission reduction strategies. Observed non-linearities in terrestrial sulphur emission-deposition
patterns have been identified in north west Europe due to increases in marine emissions, and are currently slowing the recovery
of freshwater ecosystems. Changes in the relative amounts of SO2 and NH3 in air over the last two decades have also changed the affinity of terrestrial surfaces for SO2 and have therefore changed the deposition velocity of SO2 over substantial areas. The consequence of this effect has been the very rapid reduction in ambient SO2 concentration in some of the major source areas of Europe, where NH3 did not change much. Interactions between the different pollutants, generating non-linearities are now being incorporated
in long-range transport models to simulate the effects of historical emission trends and to provide projections into the future.
This paper identifies non-linearities in emission deposition relationships for sulphur and nitrogen compounds in Europe using
data from the EMEP long-rang transport model and measured concentration fields of the major ions in precipitation and of SO2 and NO2 in surface air. 相似文献
79.
80.
Brian P. Leaderer Rebecca T. Zagraniski Jan A. J. Stolwijk 《Environmental management》1977,1(1):31-37
A method is presented here by which the actual numbers of individuals in the U.S. population who would be expected to suffer respiratory illness as a result of exposure to ambient nitrogen dioxide (NO2) concentrations in excess of the Federally-designated ambient air quality standard can be estimated. At the same time we have attempted to quantify how these adverse health effects would be alleviated by various degrees of reductions in current ambient concentrations. In addition, the health benefit expected to be derived by various NOx emission control strategies will be examined utilizing the health benefit estimation method presented.It is estimated that there were approximately 33.2×106 excess cases of respiratory illnesses in the U.S. in 1973 associated with ambient NO2 concentrations in excess of the national ambient standard. A reduction of approximately 50 to 60 percent below 1973 NO2 levels is needed to essentially eliminate excess respiratory illness associated with ambient NO2 concentration. 相似文献