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1.
In this paper estimates of dry and wet deposition of acidifying substances in the Netherlands are presented. The deposition was estimated from measured concentrations in the atmosphere and in precipitation or if these were not available, from modelled concentrations. The method was applied for the Netherlands on a 5×5 km scale. The most important components are sulphur oxides and ammonia and their reaction products. It was estimated that the annual average deposition of SO x in the Netherlands decreased from 1570 to 670 mol ha?1 a?1 between 1980 and 1989. In 1989, the annual average NO y deposition was estimated to be 1220 mol ha?1 a?1 in 1980 and 1160 mol ha?1 a?1 in 1989. The annual average NH x deposition in the Netherlands was estimated to be 2330 and 2190 mol ha?1 a?1 in 1980 and 1989 respectively. HCI deposition was about 100 mol ha?1 a?1 in all years. Dry deposition contributes most to the total deposition for each component. The spatial distribution of the total deposition shows a gradient over the Netherlands with highest values in the South and lowest in the North of the country. Meteorological conditions are also of influence on the deposition fluxes for all components. During 1988 and 1989 meteorological conditions favoured low deposition. The estimated uncertainty in the average fluxes of SO x , NO y , and NH x for the Netherlands is 15, 25, and 30% respectively. The wet deposition fluxes can be estimated more accurately than the dry deposition.  相似文献   

2.
Woo  J.-H.  Baek  J. M.  Kim  J.-W.  Carmichael  G. R.  Thongboonchoo  N.  Kim  S. T.  An  J. H. 《Water, air, and soil pollution》2003,148(1-4):259-278
Emissions in East Asia for 1993 by administrative units and source types are estimated to support regional emission assessments and transport modeling studies. Total emission of SOx, NOx, soil NOx, N2O, and NH3 are 24 150, 12 610, 1963, 908, and 8263 kton yr-1, respectively.China's emission contribution is the highest for every species.The area sources are the most significant source type for SOx and NOx, but the fraction due to mobile source is highest for NOx. Major LPSs are located from the middle to the east part of China, south and middle-west part of South Korea, and the east part of Japan. The area sources of SOx show a pattern similar to population density, whereas NH3 shows a strong landuse dependency. Detail emissions analysis reveals higher SOx emission `cores' within each province. The estimated emissions are used to estimate sulfur deposition in the regions. The seasonal average sulfur distribution amounts are estimated from the ATMOS2 chemical transport model. The results showed anti-correlation with temperature for sulfur (SO2 + SO4 -2) concentrations and a positive correlation with rainfall for deposition.  相似文献   

3.
An eulerian long-range transport model for the calculation of concentrations of SO2, SO4, NO x , and NO3 and wet and dry depositions of SO x (sum of SO2 and SO4) and NO y (sum of NO, NO2 and NO3) over Europe is presented. The model is developed in such a way that only routinely available, analyzed or prognostic meteorological fields are required as input data. In this way it is possible to obtain a forecast of the air quality during smog episodes. For evaluation of smog episodes the model provides a way to estimate the contributions of different sources and the effect of emission scenarios. The model has been evaluated for four winter and three summer episodes. The modeled concentrations of SO2 and SO, are in agreement with the available measurements. A less good agreement is found for NO2 and NO x (sum of NO and NO2) concentrations. For these components the model tends to underpredict the measured values.  相似文献   

4.
The contributions of the anthropogenic sources of NOx from various combinations of contiguous U.S. states or Canadian provinces to integrated deposition across selected states or provinces are estimated with the Advanced Statistical Trajectory Regional Air Pollution (ASTRAP) model. The model assumes linearity between emissions and deposition, and uses the same parameterization methods, although with different rates, as in simulations of transport and deposition of SOX. Vertical distributions of emissions for the two classes of pollutants are substantially different in the gridded inventories used in simulations, with a weighted mean effective emission height of 160 m for NOX and 310 m for SOX. This might be expected to lead to an effective transport distance before deposition shorter for NOX than for SOX. However, the calculated fraction of NOX emissions deposited within the contiguous United States and Canada south of 60 deg N (57%) is not greatly different from the fraction calculated for SOX emissions (54%). This suggests that there may be compensating factors in the horizontal distribution of NOX emissions, and in the lower dry deposition velocities for NO/NO2 than for SO2 in ASTRAP.  相似文献   

5.
For the January 1985 smog episode concentrations of SO2, sulphate (SO4), NO x (sum of NO and NO2) and nitrate (NO3) have been calculated for north-western Europe by means of an atmospheric transport model. The unfavorable dispersion conditions (moderate to low wind speeds, a low mixing height and a strong inversion) and a reduced dry deposition over the snow-covered or frozen soil, in combination with increased space heating emissions due to the exceptionally cold weather, gave rise to high ground level concentrations. In order to study the effectiveness of control measures during this type of episodes, calculations were made for various emission scenarios. The results were evaluated for four receptor areas, two areas relatively close to the major sources (The Netherlands and the Black Forest) and two more remote areas (Scotland and the SW coast of Sweden, near Gothenburg).  相似文献   

6.
Epidemiology studies relating health effects to ambient levels of ozone and fine particles have led to the modification of standards in the United States for these pollutants (substitution of an 8-h standard for ozone at 80 ppbv, and addition of 24-h and annual standards for fine particles). The interrelationships of these pollutants in the atmosphere suggest the need for an integrated, science-based strategy for their control. Secondary ozone formation has been controlled through emission controls on VOC and NOx precursors. Fine particles are secondary products largely resulting from the oxidation of precursors (SO2, NOx, and VOCs). The key intermediates in both types of secondary process are free radical species and the photochemically labile compounds that produce them in the atmosphere. However, due to the complex and nonlinear nature of the processes, reductions in precursors may lead to unexpected changes in ozone and fine particle formation rates. For example, reduction in NOx emissions may reduce ozone and nitric acid levels, but lead also to increased rates of sulfate formation in clouds and increased ammonia availability for neutralization of acidic sulfate aerosols. Reductions of SO2 may reduce aerosol sulfate levels in the summer, but have no effect in other seasons. Reductions in VOCs may reduce ozone levels in urban core areas, but not elsewhere. An integrated, regionally and seasonally specific, emission reduction strategy is needed to cost-effectively reduce both ozone and fine particle levels.  相似文献   

7.
This paper describes a computational system developed for the compilation of an anthropogenic emission inventory of gaseous pollutants for Greece. The inventory was developed using a geographical information system integrated with SQL programming language to provide high temporal gridded emission fields for CO, NO2, NO, SO2, NH3 and 23 non-methane volatile organic compounds (NMVOCs) species for the reference year 2003. Activity and statistical data from national sources were used for the quantification of emissions from the road transport, the other mobile sources and machinery sectors and from range activities using top-down or bottom-up methodologies. Annual emission data from existing national and European emission databases were also used. The emission data were spatially and temporally disaggregated using source-specific spatiotemporal indicators. On national scale, the road transport sector produces about 60% of the annual CO and NMVOC total emissions, with gasoline vehicles being the main CO and NMVOC emissions source. The road transport is responsible for approximately half of the higher alkanes and for more than half of the ethene and toluene emissions. The maritime sector accounts for about 40% of the annual total NOx emissions, most of which are emitted by the international shipping subsector, whilst SO2 is emitted mainly by the energy sector. The evaluation of the emissions inventory suggests that it provides a good representation of the amounts of gaseous pollutants emitted on national scale and a good characterisation of the relative composition of CO and NOx emission in the large urban centres.  相似文献   

8.
Calculating nitrogen deposition in Europe   总被引：1，自引：0，他引：1  
Nitrogen deposition calculations for Europe were performed by separate models describing the long-range transport of ammonia and oxidized N. A linearized version of a non-linear atmospheric chemistry model was used for calculating oxidized N. Model computations were found to be consistent with the observed spatial pattern of wet nitrate deposition in Europe. Interannual meteorological variability was estimated to cause a typical year-to-year variation in annual oxidized N deposition of about 6 to 10%. Nitrogen deposition was computed for several NO x emissions reduction scenarios. These scenarios were derived from an OECD study and applied to the 27 largest countries in Europe. Most reduction scenarios affected the deposition pattern of oxidized N, but the most extreme NO x emission reduction scenario did not change very much the overall pattern of total (oxidized N plus ammonia N) N deposition. Depending on the desired level of environmental protection, it may be necessary to reduce ammonia emissions in addition to NO x emissions in order to reduce N deposition in Europe.  相似文献   

9.
One-year field measurements were conducted in a Japanese cedar (Cryptomeria japonica) forest, located in Gunma Prefecture, Japan. On the basis of the meteorological and atmospheric concentration data, the dry deposition of SO2, HNO3, NO2 and HCl was estimated using the inferential method. The annual dry deposition of H+ was estimated at 721 eq ha?1yr?1, which was 40% larger than the measured annual wet deposition of H+ (514 eq ha?1yr?1). Therefore, dry deposition is an important pathway for the atmospheric input of H+ to the forest in the study site. The contribution of each gas to the dry deposition of H+ was as follows: SO2, 25%; HNO3, 32%; NO2, 10%; and HCl, 33%. The extremely high contribution of HCl appeared to be caused by the high emission intensity of HCl due to waste incineration in the site region. The differences between estimated deposition and throughfall and stemflow measurements indicated that about 80% of the total deposition of H+ was taken up by the canopy.  相似文献   

10.
Extensive wet deposition monitoring data, along with much sparser dry deposition monitoring data and isolated field characterizations of droplet deposition, are used to produce an annual deposition budget for S and NOx-N for each contiguous U.S. state and Canadian province. The contribution to wet deposition from natural sources is estimated, and wet deposition is adjusted accordingly, to focus the analysis on deposition associated with anthropogenic emissions. The budgets, which are appropriate for 1985–1987, include adjustments for increased local wet and dry deposition near point sources and urban areas, which are generally avoided in selecting monitoring sites. When aggregated over the United States and Canada, estimated wet, dry, and droplet deposition account for about 30, 29, and 4% of anthropogenic S emissions, respectively, implying that 37% is exported. For NOx-N, estimated wet, dry, and droplet deposition account for 30, 43, and 4% of anthropogenic emissions, with 23% exported. Results are in general agreement with a variety of other observational analyses and regional modeling simulations, particularly for eastern North America, and are consistent with estimates of net horizontal mass fluxes of S and NOx-N across the Atlantic coast of North America.  相似文献   

11.
Metcalfe  S. E.  Derwent  R. G.  Whyatt  J. D.  Dyke  H. 《Water, air, and soil pollution》1998,107(1-4):121-145
It is now recognised that a multi-pollutant, multi-effect approach needsto be adopted to address the range of problems caused by atmosphericpollution. In this paper we use a relatively simple trajectory model (HARM)to explore the coupled behaviour of sulphur dioxide (SO2),oxides of nitrogen (NOx) and ammonia (NH3) andthe possible effects of future reductions in emissions of these pollutantson depositions of S and N across Great Britain. The performance of HARM withrespect to concentrations and depositions of NOy andNHx is assessed by comparison with data from nationalmonitoring networks. A range of emissions scenarios are modelled and theeffects of these reductions on critical loads exceedance are explored usingthe critical loads function (CLF), which allows both the acidification andeutrophication effects of S and N deposition to be explored simultaneously.Spatial variations in the reductions of deposition of S and/or N required tomeet critical loads are described. Reductions in emissions of the precursorsof strong acids (SO2 and NOx) yield benefits interms of ammonium deposition as a result of their coupled chemistry. Thedevelopment of strategies to control nitrogen deposition will need to take this non-linearity in to account.  相似文献   

12.
Regional oxidant distributions produced under various atmospheric conditions and emission scenarios are investigated using the Regional Acid Deposition Model (RADM). RADM is a complex, evolving three-dimensional Eulerian model that describes the chemistry, transport and deposition of tropospheric trace species including SO2, sulfate, NO x and volatile organic compounds as well as O3, other major oxidants and acids. The model calculates the short-term temporal evolution of atmospheric trace gas concentrations and their deposition on the regional scale. This study is focused on oxidant production in the eastern United States and southeastern Canada. The influence of atmospheric conditions is explored by comparing three characteristic winter, summer and spring/fall cases. Base-case 1985 emissions of SO x , NO x , volatile organic compounds (VOCs), NH3 and CO are specified using the comprehensive pollutant emissions inventory developed as part of the National Acid Precipitation Assessment Program (NAPAP). The perturbed case, which represents projected anthropogenic emission changes for 2010, indicates changes in daily total 80 km grid average NO x emissions ranging from increases of 75% to decreases of 45% and VOC emission changes ranging from increases of 65% to decreases of 20%. The largest NO x emission changes occur in the northeast, and the largest VOC changes occur in the Gulf Coast area. Ground level grid average midday O3 concentrations for the 1985 emission cases are highest (on the order of 70 to 100 ppb) in the New York City and Houston metropolitan areas for the summer and spring cases; the summer case also indicates relatively high grid average O3 concentrations of greater than 80 ppb in the southeast. Winter case values are much lower than summer O3 values throughout the region, with highs of 40 to 50 ppb occurring in the southeast and the Great Lakes area. Changes in NO x and other emissions under the complex 2010 emissions scenario for the summer case result in maximum O3 concentration reductions of 10% in the Houston area and increases in O3 of a few percent in some rural areas of the southeast. This study underscores the need for more comprehensive assessment of the complex relationships among regional emission changes, oxidant production and atmospheric conditions.  相似文献   

13.
The concentration of nitrate in both wet and dry deposition has both increased historically and currently, and recently parallels emissions in NOx. Since NOx is produced in amounts comparable to SO2, it is an important contributor to acid deposition, and is produced in higher amounts in urban areas due to concentrated sources. Prior to this study, national acid deposition monitoring networks in the United States have been and remain established in non-urban areas. This research study consisted of a comparison of precipitation sampling and analysis of wet deposition nitrate and pH for each deposition event in each of two urban sites over a 15 mo period. Also, a comparison of urban data and data generated at a nearby non-urban NADP site was made by examination of both monthly and seasonal data. This research suggests that national monitoring programs should consider inclusion of urban and non-urban monitoring sites in order to achieve a more representative regional assessment.  相似文献   

14.
Aircraft measurements of the air pollutants SO2 and sulfate (SOx is defined as SO2 plus sulfate), plus data on wind velocity, wind direction and depth of the planetary boundary layer, enable the calculation of transboundary mass fluxes of SOx. When emission data are available, an emission-deposition balance of SOx can be determined. The results of a measurement flight, carried out on 12 February, 1986, are presented. Two tracks were flown, along the eastern and along the western border of the Netherlands, respectively. The wind was easterly. The calculated deposition flux of SOx is converted to an area-averaged dry deposition velocity (ν d ). The result, ν d = 1.2 × 10?2 m s?1, seems to be in good agreement with literature data.  相似文献   

15.
A large amount of pollutants in highly industrialized areas is produced by a photochemical reaction of NO x and SO x , which is a result of the production of energy-related fuel combustion. These pollutants provide the major source of condensation nuclei for the formation of fog in the areas of busy highways, airports, seaports, etc. The present study simulates how these pollutants affect the formation of advection fog. Both microphysical and macrophysical processes are considered in investigating the time dependent evolution of the spectra of condensation nuclei associated with both polluted and clean atmospheres during the time period of advection fog formation. In the first part of the series of this paper, the initial aerosol population concerns a monodisperse, multi-component aerosol model. The results show that both SO x , and NO x as condensation nuclei provide great contributions in the formation of advection fog.  相似文献   

16.
A long-term modelling (1991–1994) of oxidised sulphur, bound nitrogen and some heavy metals has been carried out by MSC-E/EMEP for the Northern Hemisphere. The transport unit of the model is an Eulerian scheme which could be classified as Pseudo-Lagrangian one. Vertical distribution described by means of Gaussian approximation and the exchange with the free troposphere are taken into account. Vertical movement is calculated proceeding from local mixing conditions, state of the surface, its height (topography) etc. The chemical unit for acid compounds contains 25 reactions and 14 compounds including sulphur and nitrogen compounds peroxyacetylnitrate, tropospheric ozone, volatile hydrocarbons (but methane) are considered as a whole via ozone creation potential. The model time step is 1 hour, meteorological data (winds, temperature, precipitation etc.) cover 6-hour intervals. The model results show that very significant part of the Arctic and West Asian acid pollution is produced by European countries. On the whole the Arctic pollution by SOx, NOx and NHx comes from sources of Old World. The main source of sulphur pollution is located in Russia and of nitrogen compound — in Central and Northern Europe. About 50% SOx, 70% NOx and 40% NHx deposition in Central Asia and Kazakhstan is-imported from external sources. A similar situation is observed in European and Asian parts of Russia.  相似文献   

17.
Nitrogen (N) budget was estimated with dissolved inorganic N (DIN) and dissolved organic N (DON) in a forested mountainous watershed in Tsukui, Kanagawa Prefecture, about 50 km west of Tokyo in Central Japan. The forest vegetation in the watershed was dominant by Konara oak (Quercus serrata) and Korean hornbeam (Carpinus tschonoskii), and Japanese cedar (Cryptomeria japonica). Nitrate (NO3 ?) concentration in the watershed streamwater was averagely high (98.0 ±± 19 (±± SD, n = 36) μmol L?1) during 2001–2003. There was no seasonal and annual changes in the stream NO? 3 concentration even though the highest N uptake rate presumably occurred during the spring of plant growing season, a fact indicating that N availability was in excess of biotic demands. The DON deposition rates (DON input rates) in open area and forest area were estimated as one of the main N sources, accounting for about 32% of total dissolved N (TDN). It was estimated that a part of the DON input rate contributed to the excessive stream NO? 3 output rate under the condition of the rapid mineralization and nitrification rates, which annual DON deposition rates were positively correlated with the stream NO3 ? output rates. The DON retention rate in the DON budget had a potential capacity, which contributed to the excessive stream NO? 3 output rate without other N contributions (e.g. forest floor N or soil N).  相似文献   

18.
The primary object of this paper is to provide a preliminary assessment of the effectiveness of NO x vs Volatile Organic Compounds (VOC) emissions control options in improving O3 air quality over the New York metropolitan area. To this end, we have applied the Urban Airshed Model (UAM) with the Carbon Bond IV (CB-IV) chemical mechanism utilizing the results of the Regional Oxidant Model (ROM) for the specification of initial/boundary concentrations and wind fields to the UAM. After examining the sensitivity of the predicted O3 concentrations to initial/boundary conditions and biogenic emissions, we have evaluated the impact of various hypothetical emissions reduction options on O3 air quality. Nested ROM/UAM simulations with an across-the-board reduction of 75% in the NO x and VOC emissions from sources located within the New York metropolitan area indicate that the option of VOC-only control is superior to the NO x -only control in reducing not only peak O3 levels over the entire modeling domain but also population exposure to unhealthy O3 levels. The model predicts that the combined 75% NO x and VOC control option also reduces the peak O3 concentration, but the improvement in O3 air quality is less than that predicted for the 75% VOC-only control strategy. Additional modeling analyses with different mix and levels of emissions control and meteorological conditions are needed to confirm these preliminary findings.  相似文献   

19.
Acid deposition is a serious problem throughout much of Asia. Emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx) have been increasing steadily, as nations strive to increase their levels of economic development. Coal and fuel oil have been the main choices for powering industrial development; and, until recently, only a few countries had taken steps to avert the atmospheric emissions that accompany fuel combustion. This paper discusses trends in emissions of SO2 and NOx that have occurred in Asian countries in the period 1985–1997, using results from the RAINS-Asia computer model and energy-use trends from the IEA Energy Statistics and Balances database. Emissions of SO2 in Asia grew from 26.6 Tg in 1985 to 33.7 Tg in 1990 and 39.2 Tg in 1997. Though SO2 emissions used to grow as fast as fossil-fuel use, recent limitations on the sulfur content of coal and oil have slowed the growth. The annual-average emissions growth between 1990 and 1997 was only 2.2%, considerably less than the economic growth rate. Emissions of NOx, on the other hand, continue to grow rapidly, from 14.1 Tg in 1985 to 18.7 Tg in 1990 and 28.5 Tg in 1997 (6.2% per year between 1990 and 1997), with no signs of abating. Thus, though SO2 remains the major contributor to acidifying emissions in Asia, the role of NOx will become more and more important in the future.  相似文献   

20.
We sampled and analyzed individually, edible dorsal muscle from largemouth bass (LMB), Micropterus salmoides (n?=?138) and yellow perch (YP), Perca flavescens (n?=?97) from 15 lakes to investigate potential local impacts of mercury emission point sources in northeastern Massachusetts (MA), USA. This area was identified in three separate modeling exercises as a mercury deposition hotspot. In 1995, 55% of mercury emissions to the environment from all MA sources came from three municipal solid waste combustors (trash incinerators) and one large regional medical waste incinerator in the study area. We determined the mercury accumulation history in sediments of a lake centrally located in the study area. Recent maximum mercury accumulation rates in the sediment of the lake of ~ 88 μg/m2/year were highly elevated on a watershed area adjusted basis compared to other lakes in the Northeast and Minnesota. Fish from the study area lakes had significantly (p?=?0.05) greater total mercury concentrations than fish from 24 more rural, non-source-impacted lakes in other regions of the state (LMB n?=?238, YP n?=?381) (LMB: 1.5–2.5 x; YP: 1.5 x). The integration of this extensive fish tissue data set, depositional modeling projections, historical record of mercury accumulation in sediments of a lake in the area, and knowledge of substantial mercury emissions to the atmosphere in the area support designation of this area as a mercury depositional and biological concentration hotspot in the late 1990s, and provides further evidence that major mercury point sources may be associated with significant local impacts on fisheries resources.  相似文献   

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