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1.
This work describes the evolution of NO2 and O3 levels from January to December of 2007, covering the four seasonal periods in the urban air of Ciudad Real in the central-southern Spain. The measurements were carried out by means of passive samplers (Radiello® samplers). Eleven samples were collected weekly, placed at different monitoring site locations. The data indicate that the mean levels obtained during this period for O3 and NO2 were 38.5?±?3.5 and 20.8?±?3.8 μg/m3, respectively. These measurements were compared with other studies in Ciudad Real. Meteorological conditions (temperature, pressure, humidity relative, wind speed and direction) were also investigated.  相似文献   

2.
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 SO4 =/NO3 ? 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 SO4 =/NO3 ? ratio for individual rain events in Warren reflected the SO2/NOx emission ratio in the area from which the event had come. Thus, the highest SO4 =/NO3 ? 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 SO4 = and the basicity was due to soil-related materials. Gaseous HNO3 averaged 2.0 μg m?3while the basic gas, NH3, averaged 0.83 μg m?3. Based on these measurements, it was estimated that dry deposition of particles and HNO3 contributed less than 10% of the total deposition of acidity during this study period.  相似文献   

3.
Atmospheric gases and particulates were collected using four-stage filter-pack in Chunchon from January through December in 1999. Particulate SO4 2? and NO3 ?, and gaseous HNO3, SO2 and NH3 were analyzed. Annual average concentration of SO4 2?(S), NO3 ?(S), HNO3 (g), SO2(g) and NH3(g) were 5.75µg/m3, 4.98µg/m3, 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 NH3 and HNO3.  相似文献   

4.
The ambient concentration of SO2, NOx and Ox in the atmosphere of Hiroshima, Fukuyama and Fuchu city which were monitored by the prefectural monitoring stations, are examined to give a picture of the typical air pollution at these sites. Results show that the yearly concentrations of SO2 in these areas are significantly fall from 20 to 6 ppb during 1978–1996 when the NOx concentrations having no such significant change which varies from 40 to 30 ppb. The Photo-chemical Oxidant (Ox) increases annually at the rate of 0.3 ppb to 0.6 ppb in Hiroshima city only. To know the present situation of air pollution the Differential Optical Absorption Spectroscopy (DOAS) system is used in the city of Higashi Hiroshima. The daily average concentrations of SO2, NO2, O3 and HONO measured during the period of August 1999 to March 2000 ranged from 1.4 ppb to 2.8 ppb, 13 ppb to 26.9 ppb, 21 ppb to 53.6 ppb and 1 ppb to 4.3 ppb respectively. The patterns of concentrations of NO2 and O3 measured by DOAS look similar to the seasonal patterns of NOx and Ox by the conventional system.  相似文献   

5.
The investigation of SO2, NO2, soot and benzo(a)pyrene (BP) has been performed at the background station on the eastern coast of the Baltic Sea since 1980. A significant decreasing trend has been observed for SO2 and NO2, while soot and BP concentrations were changing insignificantly. The decreasing SO2 and NO2 high concentrations (>10µg·m?3) have been determined in the air masses coming from the Western and Central Europe to Lithuania since 1900. The concentration of SO2 in a range of 0–5µg·m?3 and the concentration of NO2 in a range of 0–10µg·m?3 are characteric of the background atmospheric air.  相似文献   

6.
In order to estimate the influence of NH3 on a forest in a clean atmosphere, the quality of the atmosphere in Sumava, South-Bohemia, was determined in September–October 1988. In this period the NOX, SO2, and aerosol concentrations were extremely low. The N-input into the forest margin amounted to 10–15 kg ha?1 in these two months, based on a deposition velocity of 3 cm s?1 and an average concentration of 9 μg m?3 NH3. The maximum hourly average ozone concentrations were found to be 50 to 100 μg m?3. There exists a strong relation between the ambient NH3 concentration profiles and the stable occupation. The concentration inside the stables exceeded the no-adverse-effect level for cows of 7.6 mg m?3. This publication forms the basis for the estimation of the exposure of the forest to NH3 and the interpretation of the observed effects as published elsewhere (Mejst?ík et al., unpublished).  相似文献   

7.
This study was carried out to evaluate acid depositions and to understand their effect. Wet precipitation has been collected at twenty-four sites in Korea for one year of 1999. The ion concentrations such as H+, Na+, K+, Mg2+, NH4 +, Ca2+, Cl?, NO3 ? and SO4 2? were chemically analyzed and determined. Precipitation had wide range of pH(3.5～8.5), and volume-weighted average was 5.2. The contribution amounts of Cl?, SO4 2? and NO3 ? in anion were shown to be 54%, 32%, and 14%, respectively and those of Na+ and NH4 + in cation were 32% and 25%. The ratios of Cl? and Mg2+ to Na+ in precipitation were similar to those of seawater, which imply that great amount of Cl? and Mg2+ in precipitation could be originated from seawater. The concentration of H+ is little related with SO4 2?, NO3 ? and Cl? ions, whereas nss?SO4 2? and NO3 ? are highly correlated with NH4 +, which could suggest that great amount of SO4 2? and NO3 ? exist in the form of ammonium associated salt. The annual wet deposition amounts (g m?2year?1) of SO4 2?, NO3 ?, Cl?, H+, NH4 +, Na+, K+, Ca2+ and Mg2+ were estimated as 0.88～4.89, 0.49～4.37, 0.30～9.80, 0.001～0.031, 0.06～2.15, 0.27～4.27, 0.10～3.81, 0.23～1.59 and 0.03～0.63.  相似文献   

8.
The long range transport of mineral dust such as Yellow Sand (YS) is not restricted to the springtime periods in Northeast Asia. A YS phenomenon was observed during 25～27 January 1999, which was a remarkably distinctive episode in the occurrence time and intensity that had ever been observed in the wintertime in Korea. This YS event had a bi-modal temporal structure with the daily average concentrations of 210～349 µg m?3. The long-lasted second one followed the first arriving short and strong dust pulse. The dominant ion components were SO4 2?, NO3 ?, Ca2+ and Na+ with the concentration of 11.3, 7.6, 6.1 and 4.2 µg m?3, respectively during the passage of YS, compared to the corresponding concentrations of 4.1, 4.6, 0.4, and 1.2 µg m?3 after the passage of YS (AYS) over Korea. The mode diameter of these compounds of YS was around 4 µm, compared to 0.4～0.9 µm of AYS. Concentrations of SO4 2? and NO3 ? were found to be highly correlated with that of Ca2+ in the coarse mode during the YS event, whereas they were well correlated with NH4 + during the non-YS period.  相似文献   

9.
Rain samples were collected sequentially by amount (≈2.7 mm each) from individual events at a single, relatively isolated, suburban site from August 1977 to July 1980. Rain pH's for ≤ 3 mm samples closely fit a monomodal Gaussian distribution with a median of 4.50 and a standard deviation of 0.39. The variability in pH was primarily interevent as opposed to intraevent. The 3-yr volume-weighted pH was 4.35 ± 0.02 for 3.16 m collected; annual pH's were 4.31, 4.37, and 4.38, and cumulative H+ deposition was 141 mg H+ m?2. Event-averaged rain pH and meteorological and air quality data were correlated. Low pH was associated with low rainfall volume and rate; rain after several dry days; rains with northeast surface winds; high SO2, NO2, and O3 in the ambient atmosphere; and high, strongly correlated, SO4 = and NO3 ? rainwater concentrations. The lowest 3-yr seasonal average pH (4.31) occurred during summer; values for other seasons were ≈4.37. Average intraevent H+ molarity (volume-weighted) was accurately characterized by 6.89 E?5 *(mm ram)?0.215. The relative merits of composite (e.g., whole event) and sequential sampling are examined.  相似文献   

10.
Casuarina cunninghamiana and Eucalyptus camadulensis (Egyptian var.) plants were exposed to 0.20 and 0.40 μL L?1 O3, SO2 or NO2 for 6 hr daily for 10 days. Eucalyptus plants were very sensitive to SO2 and NO2 and less sensitive to O3. Casuarina plants were insensitive to the 3 gases. The rate of sorption of the 3 gases was estimated over a 10 day exposure to 0.20 μL L?1 pollutant concentration singly and in a 3-gas mixture. Casuarina plants removed air pollutants more efficiently than Eucalyptus plants. Leaves of both species generally sorbed about the same volume of a given gas from the mixture and from the same single gas. The sorption rate over the 10 day exposure was almost constant after a higher sorption rate during the first day for both species.  相似文献   

11.
A simple method to assay inorganic pyrophosphatase activity in soils is described. It involves extraction and colorimetric determination of the orthophosphate (Pi) released when 1 g soil is incubated with buffered (pH 8) pyrophosphate (PPi) solution at 37°C for 5 h. The 1 n H2SO4 used to extract Pi gives quantitative recovery of Pi added to soils, and the colorimetric method used to determine the Pi extracted in the presence of PPi is specific for Pi. The inorganic pyrophosphatase activity of the six soils studied ranged from 50 to 450 μg Pi released·g?1 soil·5 h?1. Steam sterilization (121°C for l h), formaldehyde, fluoride, oxalate, and carbonate inhibited and toluene, Na+, K+, NH+4, Cl?, NO?3, NO?2, SO2?4, and EDTA had no effect on the activity of this enzyme in soils. The initial rates of Pi released obeyed zero-order kinetics. The temperature dependence of the rate constant conformed to the Arrhenius equation up to the point of enzyme inactivation (55°C). The activation energy of pyrophosphatase activity of the six soils studied ranged from 32.5 to 43.2 (av 36.1) kJ·mole?1. Application of the three linear transformations of the Michaelis-Menten equation indicated that the Km values of PPi for pyrophosphatase in four soils ranged from 20 to 51 (avg. 35) mM and that the Vmax ranged from 130 to 830 (av 500) μg Pi released g?1 soil·5 h?1. Studies of other properties of inorganic pyrophosphatase activity in soils are reported.  相似文献   

12.
The present work discusses the startup and operation of different biotrickling filters during the simultaneous removal of NH3, H2S, and ethyl mercaptan (EM) for odor control, focusing on (a) the impact of pH control in the stability of the nitrification processes during reactor startup and (b) the crossed effects among selected pollutants and their by-products. Two biotrickling filters were packed with poplar wood chips (R1 and R2A), while a third reactor was packed with polyurethane foam (R2B). R2A and R2B presented a pH control system, whereas R1 did not. Loads of 2?C10?g N?CNH3 m?3?h?1, 5?C16?g S?CH2S m?3?h?1, and 1?C6?g EM m?3?h?1 were supplied to the bioreactors. The presence of a pH control loop in R2A and R2B proved to be crucial to avoid long startup periods and bioreactors malfunctioning due to biological activity inhibition. In addition, the impact of the presence of different concentrations of a series of N species (NH 4 + , NO 2 ? , and NO 3 ? ) and S species (SO 4 2? and S2?) on the performance of the two biotrickling filters was studied by increasing their load to the reactors. Sulfide oxidation proved to be the most resilient process, since it was not affected in any of the experiments, while nitrification and EM removal were severely affected. In particular, the latter was affected by SO 4 2? and NO 2 ? , while nitrification was significantly affected by NH 4 + . The biotrickling filter packed with polyurethane foam was more sensitive to crossed effects than the biotrickling filter packed with poplar wood chips.  相似文献   

13.
Observations on gaseous and particulate pollutants were undertaken at four locations in the region of a thermal power plant (TPP), which is under construction at Tuticorin, south India. The predicted concentrations Of SO2 due to the emissions from the TPP and its possible impact on the inhabitants and climate in the downwind region were evaluated. Also, the predicted concentrations downwind of a Petrochemical Industrial Complex (PIC) located in the vicinity of the TPP were computed and compared with the measured concentrations. The predicted maximum concentration of SO2 at 6 km downwind of TPP is about 530 μg m?3 under most favourable wind conditions. The anticipated increase in SO2 due to the thermal power plant under construction may therefore be substantial. The predicted concentrations Of SO2, at a distance of 1.8 km downwind of the PIC, varied between 34 and 216 μg m?3 for wind directions ranging from 70 to 90° and for Pasquill stability category C. The plume would be over the observational site when the wind direction is 80°. The maximum measured concentration was 23 ug m?3. The discrepancy was due to the rapid fluctuations in the wind direction during the observational period over a wide range from 20 to 90°.  相似文献   

14.
Methylcyclopentadienyl manganese tricarbonyl (MMT) is an organic derivative of manganese used as an additive in unleaded gasoline in Canada since 1977. Moreover, Canada is the only country in the world to have authorized the replacement of lead alkyls by MMT in gasoline. The purpose of the present study is to assess the importance of air contamination by Mn in relation to other air pollutants (gaseous and particulates), meteorological variables and traffic density. The concentration of both the gaseous (O3, CO, NO, NO2, SO2) and the particulate pollutants (Mn, Pb, NO? 3, SO?? 4, TSP) had been measured by the Montreal Urban Community in 1990 at seven sampling stations located in high traffic and low traffic density areas. Data on the meteorological conditions during that same period were also used. Non-parametric correlation, ANOVA and discriminant analyses were used to compare gaseous and particulate pollutants found between both levels of traffic density. In almost 50% of the daily air samples measured in 1990, the Mn concentrations are higher than the urban background level estimated at 0.04 μg m?3 and the variations of Mn concentrations are significantly correlated in time with traffic density. Moreover, Mn and TSP discriminate the best high and low traffic density areas. No significant differences have been observed between Pb, O3 and SO2 concentrations in both areas. These results should not be interpreted in terms of potential health effects since it is presently impossible to determine the fate of the Mn in the environment and its importance in terms of human exposure.  相似文献   

15.
《Journal of plant nutrition》2013,36(10):2151-2159
ABSTRACT

The impact that nitrogen (N), phosphorus (P), and potassium (K) application rates on the sulfur (S) fractions in leaves and fruits of greenhouse-grown cucumbers plants (Cucumis sativus L. cv. Brunex) are presented. The treatments were as follows: N (N1=5 g NO3NH4/m2, N2=10 g NO3NH4/m2, N3=20 g NO3NH4/m2, N4=40 g NO3NH4/m2), two levels of P (P1=8 g H3PO4/m2 and P2=16 g H3PO4/m2), and two levels of K (K1=20 g K2SO4/m2 and K2=40 g K2SO4/m2). The foliar and fruit contents were determined for total S, organic S and sulfate. The influence of the N treatments on the total S (St: organic S +sulfate) concentration, proved significant, showing a progressive increase in the leaf and fruit concentrations. In the leaves, the P slightly diminished the St concentration but values in the fruits did not appreciably differ from control. The K dosage did not cause the St concentration to differ from that of P, although in the fruit a slightly lower St concentration appeared in the K2 treatment. The response of the organic-S concentration in the leaves resembled that of St, and thus organic S should not be used as a diagnostic method for S status. In the relationship SO4 2-/St, the SO4 2- concentration proved more influential than did the St form, providing a more accurate representation of the potential status of this nutrient in the plant.  相似文献   

16.
ABSTRACT

Black walnut (Juglans nigra L.) half-sib 1+0 seedlings were exponentially fertilized with ammonium (NH4 +) as ammonium sulfate [(NH4)2SO4], nitrate (NO3 ?) as sodium nitrate (NaNO3), or a mixed nitrogen (N) source as ammonium nitrate (NH4NO3) at the rate of 0, 800, or 1600 mg N plant?1 and grown for three months. One month following the final fertilization, N concentration, growth, and photosynthetic characteristics were assessed. Compared with unfertilized seedlings, N addition increased plant component N content, chlorophyll content, and photosynthetic gas exchange. Net photosynthesis ranged from 2.45 to 4.84 μmol m?2 s?1 for lower leaves but varied from 5.95 to 9.06 μmol m?2 s?1 for upper leaves. Plants responded more favorably to NH4NO3 than sole NH4 + or NO3 ? fertilizers. These results suggest that N fertilization can be used to promote net photosynthesis as well as increase N storage in black walnut seedlings. The NH4NO3 appears to be the preferred N source to promote black walnut growth and physiology.  相似文献   

17.
A monitoring study was carried out in an alluvial fan area in Tsukui, Central Japan during the study period of 1999–2003, in order to explain selenium (Se) behaviors in ecosystem combined with air, soil and groundwater. Monthly Se concentrations in open bulk precipitation (rainfall+aerosol, gaseous deposition and etc.), soil solution (collected by porous ceramic-cup) and groundwater ranged from 0.1 to 1.4 μg L?1 (volume-weighted average: 0.34 μg L?1), 0.21 to 1.0 μg L?1 (0.48 μg L?1) and 1.6 to 2.4 μg L?1 (2.2 μg L?1), respectively. Se concentration in open bulk precipitation was negatively correlated with the rainfall amount. Se concentration in soil solution significantly increased with DOC concentration in soil solution. Besides, despite atmospheric Se input and rainfall to the grassland study area, Se concentration in soil solution and groundwater received no significant effect from the rainfall amount, pH, Se, DOC, SO4 2?, NO3 ? and EC in rainfall. Even though Se concentrations in groundwater were significantly correlated with soil solution volume, Se, DOC and NO3 ? and groundwater level, the result of multiple regression analyses (MRA) indicated that the groundwater Se was negatively influenced by groundwater level, which depended on groundwater recharge. Se was transported into the groundwater through the groundwater recharge that largely increased in this alluvial fan study area after heavy rain.  相似文献   

18.
The Arctic air mass is a unique meteorological feature of the northern hemispheric atmosphere. Possessing well-defined meteorological characteristics, it occupies not only the polar region but also a large fraction of the Canadian and Eurasian land masses during the period November to April. Poor pollutant removal by precipitation and dry deposition within the air mass and a strong transport pathway between Eurasian mid-latitudinal sources and the north, result in elevated levels of acidic anthropogenic aerosols and gases in the air mass during winter. In summer, weak north/south transport and strong pollutant removal between the Arctic and mid-latitudes and within the Arctic, results in lower airborne concentrations of acidic pollutants. Due to the presence of the relatively polluted Arctic air mass, ‘background’ air concentrations of SO4 =, SO2 and total NO3 ? are elevated in western Canada during winter. Typical mean monthly concentrations from December to March are 0.8 to 2.1, 1.0 to 2.4 and 0.1 ? 0.6 μg m?3, respectively. In the absence of the neutralizing influence of alkaline soil dust, the acidity of snow forming in western Canada during winter is expected to range from 5 to 20 μeq l ?1.  相似文献   

19.
Sandy loam soil, with added glucose, was incubated anaerobically under N2 and subjected to repeated 1-h C2H2 reduction assays. In the presence of 1% glucose the addition of 50 μg NH4+ ?N/g or of 20 μg NO?3 N/g (untreated soil contained 1.2 μg NH+4?N and 7.10 μg NO?3-N/g) caused at least some suppression of nitrogenase activity. Activity developed when the KCl-extractable soil inorganic nitrogen concentration dropped below 35 μg/g. In the presence of 0.1 or 0.05% glucose the addition of 5 μg NH+4?N/g caused some suppression of nitrogenase activity. However, activity developed when the soil NH4+-N concentration dropped below about 4 μg/g. With 0.1% glucose and 5 μg added NO?2 N/g, activity did not develop until the soil NO?2 -N concentration dropped to zero. Added NO?3 N was rapidly reduced and denitrified to NO?2- N, N2O-N and NH+4 N and furthermore caused some inhibition of CO2 evolution. The data from NH4?-addition experiments are consistent with a nitrogenase repression/ derepression threshold of 4 and 35μg NH+4-N/g at 0.05 and 1% glucose concentrations, respectively. The data from NO?2- and NO?3-addition experiments suggest a combination of repression and toxicity effects in the presence of added NO?3 N.  相似文献   

20.
A monitoring programme should be designed for duration. This means that methods should not only be appropriate with respect to detection limits and accuracy, but they should also be as simple as possible and they should be documented in such a way that measurements will be comparable over many decades. In this connection, it is particularly important to understand that results are dependent on methods, instruments and procedures. Within the European monitoring network (EMEP) there are several different sampling procedures for the main air components, SO2, NO2, SO4 2?, NO3 ? + HNO3, and co-located experiments have therefore been initiated to quantify the difference between the measurements. Reference methods and reference instruments corresponding to the recommendation in the EMEP Manual have been run together with the usual measurements at EMEP sites in several countries. The results are generally satisfactory, especially in the case where identical methods are used. However, there are also some unacceptable differences, e.g. when comparing NO2 and SO2 monitors with the reference methods. The monitors do have a main advantage of providing easily accessible data with short time resolution; nevertheless, the accuracy at low concentrations is usually poor. The traditional reference methods need development and simplification in the direction of the more appealing automatic instruments.  相似文献   

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