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1.
Atmospheric gases and particulates were collected using four-stage filter-pack in Chunchon from January through December in 1999. Particulate SO 4 2? and NO 3 ?, and gaseous HNO 3, SO 2 and NH 3 were analyzed. Annual average concentration of SO 4 2?(S), NO 3 ?(S), HNO 3 (g), SO 2(g) and NH 3(g) were 5.75µg/m 3, 4.98µg/m 3, 0.33ppb, 1.52ppb and 7.25ppb, respectively. Annual dry deposition fluxes were estimated using the measured concentration and dry deposition velocity published by other research group. Annual dry deposition of S was 287kg · (km) ?2·y ?1, which accounted for about 30% of total S deposition. For N deposition, dry deposition is predominant; about 70% of total N deposition was through dry process mostly as forms of NH 3 and HNO 3. 相似文献
2.
Ground-level dynamics of O 3, NO x and benzene, toluene, ethylbenzene and xylenes were characterised at rural sites in the medium Ebro River Basin (Northern Spain) from April to September (2003–2007) and by means of automated and passive monitoring. The study registered high O 3 levels within the area, which were influenced by traffic emissions, and a monthly evolution of these levels consistent with the occurrence of a broad summer maximum, typical of polluted areas. The mean ozone concentration registered in the studied area by means of passive sampling was 87?±?12 μg m ?3. The 2008/50/EC objective value for the protection of vegetation was widely exceeded during this study (AOT40?=?57,147?±?14,114 μg m ?3 h), suggesting that current ambient levels may pose a risk for crops and vegetation in this important agroindustrial region. 相似文献
3.
In order to investigate the acid rain formation under the coexistence of SO2(g), H2O2(g), and HNO3(g) in the air, a mathematical model has been built and some numerical simulations have been carried out with use of the model. The simulation reveals that SO2(g) absorbed into a raindrop is released and then re-absorbed as the fall distance increases. The desorption and re-absorption processes of SO2(g) are caused by: (1) the fact that the equilibrium concentration of H2O2(aq) and HNO3(aq) in raindrops are much higher than that of SO2(aq), and (2) the fact that the oxidation reaction rate of HSO3
? with H2O2(aq) increases with H+ concentration in raindrops. The degree of acidification of the rainwater has been estimated by introducing a raindrop size distribution. The acidification is mainly caused by the adsorption of SO2(g) in the usual case where the atmospheric concentration of SO2(g) is much higher than that of HNO3(g). With the increase in the atmospheric concentration of HNO3(g), the concentration of H+ generated from SO2(g) decreases and the contribution of HNO3(g) to the generation of H+ becomes dominant. 相似文献
4.
In recent years, acid rain has been a social problem all over the world. In Japan, it is also a big problem especially in the metropolitan area. Then, we have measured major ions such as H +, Na +, NH 4 +, K +, Mg 2+, Ca 2+, Cl ?, NO 3 ?, and SO 4 2? in precipitation and dry deposition samples which had been collected at 9 sampling sites at Hiyoshi, Mita, Kashiwa, Shiki, Fujisawa, Yokosuka, Mitaka, Hachiouji, and Ashikaga in Tokyo Metropolitan area for 10 years since 1990. The average pH of precipitation in their sites was 4.56 (n=1906). As the results of multiple regression analysis showed that pH of precipitation was determined by 5 ions such as NH 4 +, nssCa 2+(non sea salt calcium), nssCl ?(non sea salt chloride), NO 3 ?, nssSO 4 2?(non sea salt sulfate) in the most of the sampling sites. Therefore, it is very important to investigate the behavior of these ions to understand the acidification of rain in Tokyo Metropolitan area. In this study, a long term trend of each ion concentration in precipitation and wet deposition was also investigated the base on the data we had observed at 7 sites for 10 years by the statistical method. 相似文献
5.
This paper describes the use of dry free hanging filters, as passive samplers to determine ozone in the ambient air. The filters, with a diameter of 25?mm, were impregnated with 5,5??-disodium indigo disulphonate (IDS), a reagent for ozone. From the amount of reacted indigo compound, found on the filter, and the ozone concentration in the ambient air, a pseudo rate constant k 1, of the reaction between ozone (O 3) and IDS on the filter, is calculated. The range of measurement is between 9 and 205???g/m 3 ambient ozone. The dry filter method is specific for ozone, while the Dutch standard method NEN2789, based on an aqueous solution of IDS, has to be corrected for the presence of NO x . From wind tunnel and field experiments, k 1 proved to vary between 0.7 and 1.5?×?10 ?6?m 3?s ?1 (??g O 3) ?1 at wind velocities between 1 and 3?m/s and at an exposure time of 60?min. Within these conditions, ozone concentrations have been determined with free hanging filters in four busy streets in Yogyakarta, Indonesia and at two background sites using an average value of k 1 of 1.2?×?10 ?6. Subsequently, the traffic NO emission was estimated from the difference of the O 3 concentrations at both sides of a road. For an arbitrary situation, an NO emission of 255???g/s per metre road length was calculated. The filter method is inexpensive and practical, needs no electricity, is easily assembled and can be used to perform measurements in remote areas. It is shown here that this simple measurement technique may support air quality studies, e.g., in developing countries. 相似文献
6.
Over 3 yr of particulate measurements were made at two high elevation sites in the southern Appalachian Mountains of Tennessee and Virginia. Both dichotomous samplers and filter packs were used to obtain day and night, week-long samples for subsequent elemental and ionic analysis. Total No inf3 sup? (HNO 3 + No in3 sup? ) and SO inf4 sup2? averaged, respectively, 1.1 and 5.0 µg m ?3 at Look Rock, Tennessee and 2.0 and 6.4 µg m ?3 at Whitetop Mountain, Virginia. At Whitetop Mountain, the spring and summer seasons had the highest average SO inf4 sup2? concentrations. Seasonally, total N03 varied little. The diurnal variation of elements and SO inf4 sup2? was small. Only total NO inf3 sup? varied substantially with highest values during the day. The fine fraction (particle diameter < 2.5 µm) accounted for about 67% of the total mass. Fine mass and elemental concentrations were generally higher at Look Rock. The elements comprising the principal mass fraction of the coarse samples (2.5 gm < particle diameter < 10 to 15 µm) were of crustal origin (e.g., Al, Si, Ca, Fe) while the element comprising the principal mass fraction of the fine samples (i.e., S) was of manmade origin. Cluster analysis identified two groups of elements at Whitetop Mountain. These groups, in both the coarse and fine fraction, were associate with a soil and an automobile emission component. At Look Rock, only a soil component was obvious. 相似文献
7.
A comprehensive acid-deposition measuring station has been set up at the General Motors Technical Center site in Warren, Michigan. A second station is also being operated at a rural site near Lapeer, Michigan, which is approximately 54 km north of the Warren site. This report presents the results of this study for the June-September 1981 period. The rain composition was similar at both sites with the pH averaging 4.1 and the SO 4 =/NO 3 ? equivalence ratio averaging 2.1:1. This similarity suggests that local sources, i.e., relatively high emissions near the Warren site, and low emissions near the Lapeer site, have little effect on rain composition. The SO 4 =/NO 3 ? ratio for individual rain events in Warren reflected the SO 2/NO x emission ratio in the area from which the event had come. Thus, the highest SO 4 =/NO 3 ? ratios were observed for rains that arrived from the southeast and the lowest ratios for rains from the southwest. No rain events arrived from a northwesterly direction during this sampling period. Measurements were carried out at both sites to estimate the relative contribution of dry deposition. The ambient particulate was acidic about half the time and basic half the time. The acidity in the particulate was due to acid SO 4 = and the basicity was due to soil-related materials. Gaseous HNO 3 averaged 2.0 μg m ?3while the basic gas, NH 3, averaged 0.83 μg m ?3. Based on these measurements, it was estimated that dry deposition of particles and HNO 3 contributed less than 10% of the total deposition of acidity during this study period. 相似文献
8.
Dry deposition velocity estimates of SO, HNO 3 and SO 4 2? were computed for six locations in eastern North America using two different inferential models; a Big-Leaf model utilized by the U. S. National Dry Deposition Network (NDDN) and, a land-use based model (LUM) that has been used in the past to estimate the relative importance of dry versus wet deposition over selected Canadian regions. There were consistent differences between models that were related to the surface type, chemical species and time of year. Mean monthly dry deposition velocities based upon the 1990–91 time period were compared at two locations. The seasonal cycles in deposition velocity were similar between models, but there were considerable differences in the amplitude of the cycles. The LUM predicted about a 400% increase in S042- deposition velocity from the winter to the summer months, while there was a 50 to 100% increase in the NDDN model estimates, depending upon location. According to the LUM, HN03 deposition to crop land increased by about a factor of 6 from winter to summer, while the big leaf model predicted a 50% increase. Overall, there was better agreement for SO 2. Averaged over 12 months, the differences in deposition velocity between models were smaller and generally within the range of uncertainty associated with inferential models. For all six sites, the mean percent difference between models in deposition velocity for SO 2, HNO 3 and SO 4 2? were 13, 35 and 79, respectively. These differences highlight the effect of using different methods for estimating dry deposition and the importance of applying the same model when examining regional patterns in dry/total deposition rates. 相似文献
9.
Survey and monitoring rangelands projects is one the important plans in rangelands management. For this purpose, the survey and monitoring methods could be time-consuming and costly. Sampling strategies of plant patches are effective in sampling procedures that cause minimizing sampling variance and time. In this study, for decreasing sampling time and cost, increasing speed, plant patches parameters (including length, width, height, area, and distance between the patches) were compared. Three transects with 50 m length at three aspect slopes were located randomly systematic at the selected site with different grazing intensities. Soil samples for nitrate (NO 3?), total nitrogen (TN), ammonium (NH 4+), phosphorus (P), sodium absorption ration (SAR), soil acidity or soil reaction (pH), sodium (Na), electrical conductivity (EC), organic carbon (OC), and potassium (K) content were taken in these transects. The data were subjected to analysis of variance (ANOVA), and the average of the measured parameters in the transects was compared by Duncan Multiple Range test using SPSS 16 software. The soil characteristics compared between the regions were analyzed with Discriminant Function Analysis using STATISTICA 10 software. Results showed that the transect slope aspect and soil characteristics had an effect on measured parameters. It was suggested to withdraw the located transect at one of the North or South and West or East Slope aspects for increasing sampling efficiency. It was also suggested that to avoid time consumtion, sampling can be recorded on plant patches’ width instead of area. It is also suggested that it would be better to record the length of the plant patches instead of their area in the non-grazed zones and record the length and the width of the plant patches in the moderate- and the high-grazed zones. 相似文献
10.
In present study, pollutant effects on needle surface characteristics of Pinus sylvestris in the area affected by a nitrogen fertilizer plant have been investigated over 1994–1997 year period. Near the factory, sites with 15–25-year-old trees on a 0.5–22 km interval were chosen. Mean monthly concentrations of NO 2 and NH 3 varied across the transect in the range of 1.8–8.8 µg m ?3 and 1.8 – 69.3 µg m ?3, respectively. NH 3 concentrations exceeded the critical level (>23 µg m ?3) only in the 0.5 km vicinity. Assessment of needle surface wettability by measuring contact angles (CA) of water droplets and surface quality by measuring stomatal area covered by structural wax (SW) revealed significant (p<0.05) needle age, site, and year of sampling related differences. Comparison of SW between sites showed reliably (p<0.05) higher surface wax erosion on one-year-old needles sampled in the area, where ammonia concentration exceeds critical level. Significant correlations between site SW on one-year-old needles and distance from the pollution source, NO 2 and NH 3 concentrations were detected (r = 0.539; r = ? 0.495; r = ? 0.426; p<0.001, respectively). Correlations between CA and factors mentioned were lower. 相似文献
11.
A measurement method for the continuous and in situ analysis of atmospheric concentration of HNO 2 and HNO 3 inside and outside of clouds has successfully been established. The approach for a wet effluent diffusion denuder (parallel plate design) was adopted and performed quasi on-line with an ion chromatography unit. The air flow through the denuder was 10 1/min and at 15 minutes of preconcentration we are able to record atmospheric concentrations of 15 ng/m 3 of HNO 2 and HNO 3, respectively. Field measurements using the denuder system were done at the Mt. Brocken summit (1142 m a.s.l., Harz Mountains, Germany) in 1998 and 1999. During day-time and under clear conditions maximum values of HNO 3 up to 7000 ng/m 3 were observed. Measurements performed during cloud events assess first time our expectation that the comparatively very great specific droplet surface in clouds is a place for a heterogeneous HNO 2 formation, after nocturnal accumulation up to 320 ng/m 3 were found. Strong positive correlation between HNO 2 concentrations and those of NO 2 were obtained during and after cloud events to assess the origin of the observed nitrous acid. The HNO 2/NO 2 ratio reached 10% under humid conditions. The observed surface to volume ratios in investigated clouds were between 0.4 and 0.7. In dependence on the cloud water pH nitrite concentrations between 5–300 µg/l (1–30 ng/m 3 air) were observed. 相似文献
12.
The magnetic, nanocrystalline Fe 0.2(Co 20Ni 80) 0.8 alloy porous microfibers were prepared by the citrate gel thermal decomposition and reduction process. The morphology, chemical composition, microstructure, and magnetic properties of the microfibers were investigated by X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray, Brunauere?CEmmette?CTeller, and vibration sample magnetometer. The as-prepared magnetic, nanocrystalline Fe 0.2(Co 20Ni 80) 0.8 porous microfibers consisting of about 48 nm grains are characterized by diameters of 1?C4???m, specific surface area of 17.73?m 2/g, and specific magnetization of 196.7?Am 2/kg. The arsenic(V) absorption on these magnetic Fe 0.2(Co 20Ni 80) 0.8 porous microfibers at room temperature was determined by the ICP-AES measurement of arsenic(V) in aqueous solution. The results show that the pseudo-first-order kinetic model is consistent with the arsenic(V) adsorption process and a good correlation coefficient ( R 2?=?0.9862). By comparing among the Langmuir, Freundlich, Temkin, and Redlich?CPeterson models for adsorption isotherms of arsenic(V) onto the magnetic Fe 0.2(Co 20Ni 80) 0.8 porous microfibers at room temperature, the Freundlich model and Redlich?CPeterson model can be used to evaluate the arsenic(V) adsorption isotherm at room temperature. The arsenic(V) equilibrium absorbance of the magnetic Fe 0.2(Co 20Ni 80) 0.8 porous microfibers is up to 1.9?mg/g when the initial arsenic(V) concentration is 1.0?mg/L in aqueous solution. 相似文献
13.
SO 2 concentrations have been measured for one year at forty-five locations throughout Asia using passive samplers. Duplicate samples were exposed at each site for one month intervals. The sites were selected to provide background information on the distribution of SO 2 over wide geographical regions, with emphasis on the regional characteristics around areas estimated to be sensitive to sulfur deposition. The annual mean values ranged from less than 0.3 μg/m 3 at Tana Rata, located at 1545 m on the Malaysia Peninsula, Lawa Mandau, (Borneo) Malaysia, and Dhankuta, Nepal, to values greater than 20 μg/m 3 at Luchongguan (Guiyang) China, Babar Mahal, Nepal, and Hanoi, Vietnam. In general high concentrations were measured throughout China, with the highest concentrations in the heavy industrial areas in Guiyang. The concentrations in east Asia around the Korea peninsula were ~5 μg/m 3. The concentrations in the southeast Asia tropics were low, with no station in Malaysia and Indonesia having average concentrations exceeding 1.7 μg/m 3. The observed SO 2 concentrations were found to display a distinct seasonal cycle which is strongly influenced by the seasonality of winds and precipitation patterns. 相似文献
14.
The present study aims to establish the annual NH 3 deposition to an inland heathland in Denmark using a micro-meterological approach with passive wind-vane flux samplers. The integrating samplers were replaced at weekly intervals from May 1995 to May 1996. The average concentration, 2.05 μg m -3 at the heathland is at a moderate level when compared to heathlands in other parts of Europe. The average deposition velocity was 0.83 cm s -1 which is within the range of depositon velocities found for other heathlands in Europe. The average canopy resistance was found to be relatively high, 61 s -1. The measurements yielded a total NH 3-N deposition of 2.4 (± 0.9) kg ha -1 yr -1 with a data coverage of 71% for 1995/1996. In 40% of this time the flux is regarded as zero because the flux is not significant different from zero. In 60% of this time the significant fluxes varied from –0.052 μg m -2 s -1 (deposition equal 16.4 kg N ha -1 yr -1) to 0.089 μg m -2 s -1 (emission equal 28.2 kg N ha -1 yr -1). The method is only able to direct measure significant fluxes down to the equivalence of 0.010 μg m -2 s -1 (approximately 3.2 kg ha -1 yr -1). Therefore the exact deposition cannot be determined by the applied method at very low deposition sites such as a coastal heathland in Denmark. In a high-deposition area as in the central Netherlands the method gave significant fluxes with a 100% data coverage for a two month period. 相似文献
15.
As global mercury emissions from coal fire power plants increase with the continuing rise of coal consumption, mercury capture methods are being developed to prevent mercury??s escape into the atmosphere. Titanium dioxide (TiO 2) in the presence of ultra violet light (UV-A; ?? max ??360?nm) and oxygen will capture mercury as the solid product HgO (s). Testing the effects of TiO 2 in the presence of other pollutants has so far been limited. We have performed kinetic and product studies of mercury adsorption in the presence of the gaseous flue co-pollutant NO 2(g). We extensively studied the gas-phase reaction of NO 2(g) with Hg (g) 0 . We compared the gas-phase reaction to the same reaction performed in the presence of thin TiO 2 particle surfaces from 0 to 100?% relative humidity. The second-order rate constant was measured to be k?=?(3.5?±?0.5)?×?10 ?35?cm 6 molecules ?2?s ?1, independent of the presence of titania or the total surface area available for adsorption. Exposure of NO 2(g) to titania surfaces that were already saturated in captured mercury (HgO (s)) increased total mercury uptake onto the surface. We discuss the implications of this study to the capture of mercury emissions prior to release to the atmosphere. 相似文献
16.
Gas mixing ratios of SO 2, NO 2 and HNO 3 and nitrate and sulfate concentrations in rainwater have beenmeasured at six sites in Indonesia. The sites, Jakarta, Serang,Cilegon, Merak and Bogor, in Java, and Bukit Koto Tabang inSumatra, provide a range of pollution regimes in Indonesia.Jakarta and Bogor are heavily polluted sites in Java, whereasBukit Koto Tabang is a clean air station in a relativelyunpopulated area on the west coast of equatorial Sumatra. At thesesites rainwater was collected daily and gas samples weeklyduring 1996. The other three sites Serang, Cilegon and Merakrepresent smaller regional towns in west Java. At these sitesrainwater samples were collected weekly from June 1991 untilJune 1992.The results show that Jakarta has the highest volume-weightedmean sulfate concentrations in rainwater while the lowest weremeasured at Bukit Koto Tabang. Volume-weighted mean nitrateconcentration was about 24 μeq L -1 at Jakarta and Bogor,significantly higher than the 0.8 μeq L -1 measured atBukit Koto Tabang.Sulfur dioxide mixing ratios ranged from 4–7 ppbv in Jakarta toan average of 1.3 ppbv at Bukit Koto Tabang. Nitrogen dioxidemixing ratio was highest in Jakarta averaging 28 ppbv comparedwith the background mixing ratio of 1.2 ppbv at Bukit KotoTabang. Using dry deposition velocities estimated during aseparate study in the similar conditions of Malaysia enabled drydeposition estimates of SO 2, HNO 3 and NO 2.Results of estimated total acidic S and N deposition (wet anddry) were greater than 250 meq m -2 yr -1 at the Jakartaand Bogor sites compared with about 23 meq m -2 yr -1 atBukit Koto Tabang. At Jakarta and Bogor dry deposition accountedfor more than 50% of the total deposition estimates compared with about 20% at Bukit Koto Tabang. Such deposition rates arehigh when compared to critical loads estimated for Indonesia bythe RAINS-Asia model. In this model, critical loads in western Java and equatorial western Sumatra fall into one of twoclasses: 50–100 and 20–50 meq m -2 yr -1. Thus acidic deposition flux at Jakarta and Bogor wasfound to be above the predicted critical loads even for the moreacid insensitive soils. 相似文献
17.
Urban benzene concentration and personal exposure to benzene were measured within different urban environments in Gothenburg, Sweden. Three intensive monitoring campaigns were carried out in May 2000, February 2001 and May 2001. Three different environments were selected; two central built-up areas with different traffic densities (high and low) and one large urban park. The methods used included passive and active sampling. Passive sampling was used to retrieve spatial variability in urban benzene concentrations, while active sampling aimed to give data on personal exposure levels within the designated areas. The passive sampling showed large spatial and temporal variations in urban benzene concentrations. The benzene concentrations, ranging from 1.0 to 3.1 μg m ?3, were typically two to four times higher within the high-traffic built-up area compared to the adjacent urban park. This was mainly due to the proximity to motorised traffic. A comparison between personal exposure and active stationary measurements showed that the personal exposure levels were roughly 1.5 times higher in the heavy traffic area and 1.3 times higher in the light traffic area than the fixed benzene concentrations. The personal exposure levels in the park were equal to the active stationary benzene concentration. Given the large spatial heterogeneity within urban areas, the placement of single street level point measurements becomes crucial. Care must be taken to ensure that the measurements are actually representative when using these measurements to estimate urban concentrations and exposure levels. 相似文献
18.
This paper presents the simultaneous measurement of atmospheric concentration of gaseous NH 3, SO 2 and NO 2, and particulate NH 4 + released from the mining activities of coal-mine area, Tirap colliery, Margherita (Assam). Gas samples were collected by impinger method and were analyzed colorimetrically. The vapor-phase concentration of NH 3, SO 2, and NO 2 range between 4.7?C40.03, 1.47?C6.14, and 1.92?C2.40???g/m 3. The NH 4 + concentration in PM 10 and PM 2.5 ranges between 0.02?C0.07 and 0.008?C0.03???g/m 3, respectively. Moderately high concentrations of NH 3 and SO 2 on the first day were due to the coal-burning activity near the sampling site, while the low concentration of NO 2 is due to less vehicle density near the sampling point. All the observed concentrations are below than those reported for the urban areas and the prescribed limit fixed by National Ambient Air Quality Standard, India. Study indicates that ammonia is the major neutralizing agent for sulfate and nitrate ions present in the particulate matter during mining activities. 相似文献
19.
A field experiment was designed to evaluate the effects of differing forms of acidifying S and N compounds on the chemistry of soils and soil solutions in a low elevation coniferous forest in northern New England. Treatments consisted of O, 1500, 3000, and 6000 eq of SO 4 2? or NO 3 ? ha ?1 for the 1987 growing season applied biweekly as H 2SO 4 or HNO 3, or in a single application as dry] (NH 4) 2SO 4. Acidifying treatments resulted in a significant increase in soil solution SO 4 2? (1.2 to 2.6) or NO 3 ? (12 to 80) in the upper B horizon. Excess strong acid anion leaching was associated with an accelerated loss of base cations, particularly MG 2+ As solutions passed through the upper 25 cm of the soil profile, mean SO 4 2? concentrations decreased by 5 to 50% of the initial values, indicating that much of the applied SO 4 2? was immobilized in the upper portion of the pedon. Elevated concentrations of adsorbed and water-soluble SO 4 2? indicate that abiotic adsorption of SO 4 2? by soils is the dominant mechanism for the initial attenuation of SO 4 2? concentrations in these solutions. Other soil properties showed only small or no change due to treatments over the single growing season of this study. These results indicate that H 2SO 4, HNO 3, and (NH 4) 2SO 4 can all effectively increase strong acid anion concentrations in the soil-soil solution system. 相似文献
20.
土壤有机碳(SOC)空间分布具有时序差异性,明确样点数量对不同时期SOC预测精度影响是制定高效采样策略的基础.选取3.93×104 km2江苏北部旱地作为案例区,运用普通克里金插值方法,分析样点数量对不同时期SOC空间预测精度的影响.结果表明:不同数量样点数据集下1980年苏北旱地SOC预测值与实测值的相关系数r和均方... 相似文献
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