共查询到20条相似文献,搜索用时 0 毫秒
1.
The NO, NO 2 and N 2O emission was measured, upon application of nitrate, ammonium and both, to four Belgian soils with different characteristics. The addition of NH
4
+
caused higher NO and N 2O emissions than the addition of no nitrogen, or the addition of NO
3
–
. In contrast to the two soils with a pH of approximately 8 the two soils with a pH around 6 showed a considerable delay in production of both NO and N 2O upon the application of the ammonium, probably due to the lag-period of nitrification. The soils with a pH of 8 gave higher emissions on the application of NH
4
+
than the soils with a pH of 6. The emission of NO 2 was found to be considerably lower than the NO emission from the soils. The NO/NO 2 ratio varied between 5–25 at considerable NO emissions (>50 nmol kg –1). In the controls of soil 1 and soil 2, which showed very low NO emissions ratios of <1 were observed. The N 2O/NO ratios varied between 5–20 when NO emissions were considerable (>50 nmol kg –1). Soil 3 and 4 gave lower N 2O/NO ratios than soil 1 and 2. In the controls of soil 1 and soil 2, at low NO emissions, N 2O/NO ratios of >300 were observed. Soil 3 and 4 gave higher NO/NO 2 and lower N 2O/NO ratios than soil 1 and 2. 相似文献
2.
Composted organic wastes have been shown to reduce emissions of N2O and CH4, but little is known about the release of these gases during the composting process. This research examined the emissions of N2O and CH4 during the composting of liquid swine manure and wheat straw at two operations, one with forced aeration and the other without. The lack of aeration increased CH4 emissions to 24 times that of composting with aeration, but had no significant effect on N2O production. When total N2O and CH4 emissions from composting were compared with liquid swine manure emissions, aerated composting was found to reduce emissions to as low as 30% of those from liquid manure storage, while non-aerated composting elevated emissions up to an estimated 330% of liquid manure storage. 相似文献
3.
The current paper investigates the possibility of establishing an empirically based model for predicting the emission rate
of nitrogen oxides (NO
x
) from oil refinery furnaces, in order to continually track emissions with respect to environmental licence limits. Model
input data were collected by direct stack monitoring using an electrochemical cell NO
x
analyser, as well as a range of telemetry sensors to obtain refinery process parameters. Principal Component Analysis (PCA),
in conjunction with Partial Least Squares (PLS) regression was then used to build a series of models able to predict NO
x
emissions from the furnaces. The models produced were proven to be robust, with a relatively high accuracy, and are able
to predict NO
x
levels over the range of operating conditions which were sampled. It was found that due to structural/operational variations
a separate model is usually required for each furnace. The models can be integrated with the refinery operating system to
predict NO
x
emission rates on a continuous basis. Two models representing structurally different furnaces are considered in this paper.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
4.
Integrated pipe manufacturing industry is operation intensive and has significant air pollution potential especially when it is equipped with a captive power production facility. Emissions of SO 2, NO x , and particulate matter (PM) were estimated from the stationary sources in a state-of-the-art pipe manufacturing plant in India. Major air polluting units like blast furnace, ductile iron spun pipe facility, and captive power production facility were selected for stack gas monitoring. Subsequently, ambient air quality modeling was undertaken to predict ground-level concentrations of the selected air pollutants using Industrial Source Complex (ISC 3) model. Emissions of SO 2, NO x , and particulate matter from the stationary sources in selected facilities ranged from 0.02 to 16.5, 0.03 to 93.3, and 0.09 to 48.3 kg h ???1, respectively. Concentration of SO 2 and NO x in stack gas of 1,180-kVA (1 KW = 1.25 kVA) diesel generator exceeded the upper safe limits prescribed by the State Pollution Control Board, while concentrations of the same from all other units were within the prescribed limits. Particulate emission was highest from the barrel grinding operation, where grinding of the manufactured pipes is undertaken for giving the final shape. Particulate emission was also high from dedusting operation where coal dust is handled. Air quality modeling indicated that maximum possible ground-level concentration of PM, SO 2, and NO x were to the tune of 13, 3, and 18 μg/m 3, respectively, which are within the prescribed limits for ambient air given by the Central Pollution Control Board. 相似文献
5.
An experiment was conducted to assess the role of different concentrations of dicyandiamide (DCD), a potent nitrification
inhibitor, on temporal changes in nitrous oxide emission from sandy loam agricultural soil. It was found that with increasing
concentration of DCD i.e. from 6 to 12% of nitrogen applied in the form of urea, there was a decrease in the both average
and peak N 2O emissions. However, from 14% DCD treated soil, there was a non-significant alteration in the N 2O emission. Maximum average N 2O efflux of 217.55 μg m −2 h −1 was noted from control plots. As compared to control, there was an attenuation of 50, 58, 65, and 91% average N 2O efflux from 6, 8, 10 and 12% DCD applied pots, respectively, whereas, there was a negative average of N 2O efflux from the soil with 14% DCD treatment. The soil N content also showed a significant correlation with N 2O emission. Therefore, 12% DCD treatment has been found to be the best with regard to attenuation of nitrous oxide from sandy
loam agricultural soils. 相似文献
6.
Composting can be a source of N 2O andCH 4 production. In this investigation, differentcompost heaps of organic household waste weremonitored with the focus on potential formation ofCH 4 and N 2O in the heaps and emission ofthese gases from the heaps. The studied compost heapshad different compost ages, turning intervals andcompost sizes. The analysed compost gases containedbetween 1–3421 L of N 2O-N L -1 and 0–470 mL of CH 4 L -1. The emission rates ofN 2O and CH 4 from the compost heaps werebetween 1–1464 mg N 2O m -2 day -1 and0–119 000 mg CH 4 m -2 day -1. These verylarge differences in compost gas composition andemission indicate the importance of compostmanagement. The results also give an understanding ofwhere in the composting process an increasing emissionof N 2O and CH 4 can occur. 相似文献
7.
Seedlings of two full-sib families of loblolly pine expressing different degrees of sensitivity to O 3 were exposed to 0.05 ppm O 3, 0.10 ppm NO 2, and/or 0.14 ppm SO 2 for 6 hr/day for 28 consecutive days. The treatments were O 3, NO 2, SO 2 (each used alone), O 3+SO 2, O 3+NO 2, and O 3+NO 2+SO 2. Significant growth suppressions were noted with the relatively sensitive family in all but the the NO 2 alone treatments. The O 3+SO 2 treatment had a more significant effect than O 3 alone, but adding NO 2 had an inconsistent effect. Significant growth suppressions were noted for the relatively non-sensitive family only in the O 3+SO 2 and O 3+SO 2+NO 2 combination treatments. Adding NO 2 to O 3+SO 2 had a slightly stimulatory effect. The relatively sensitive pine family suffered a 30% height growth suppression versus a 14% height growth suppression for the relatively insensitive family when exposed to the 3 pollutant combination. Symptoms were noted on less than 4% of the foliage in the most severe treatments. The pollutant concentrations used in this study were below the National Ambient Air Quality Standards (NAAQS) for each pollutant. 相似文献
8.
This study quantified spatiotemporal patterns of CH 4 and N 2O emissions from livestock and poultry production in Turkey between 1961 and 2007. CH 4(enteric) (from enteric fermentation), CH 4(manure) (from manure management), and N 2O (AWM) (from animal waste management) emissions in Turkey were estimated at 1,164, 216, and 55 Gg in 1961 and decreased to 844, 187, and 39 Gg in 2007, contributing a share of roughly 2% to the global livestock-related CH 4 emissions and %1.5 to the global N 2O (AWM) emissions, respectively. Total CO 2-eq emissions were estimated at 50.7 Tg in 1961 and declined from a maximum value of 60.7 Tg in 1982 to a minimum value of 34.5 Tg in 2003, with a mean emission rate of 48 Tg year ???1 due to a significant reduction in the number of ruminant livestock. The highest mean share of emissions belonged to West Black Sea (14% and 16%) for CH 4(enteric) and CH 4(manure) and to North East Anatolia (12% and %13) for N 2O (AWM) and total CO 2-eq emissions, respectively. The highest emission density was 1.7 Mg km ???2 year ???1 for CH 4(enteric), 0.3 Mg km ???2 year ???1 for CH 4(manure), and 0.07 Mg km ???2 year ???1 for the total CO 2-eq emissions in the West and North East Anatolia regions and 0.09 Mg km ???2 year ???1 for N 2O (AWM) in the East Marmara region. Temporal and spatial variations in CH 4(enteric), CH 4(manure), and N 2O (AWM) emissions in Turkey were estimated using regression models and ordinary kriging at a 500-m resolution, respectively. 相似文献
9.
建立了自制浮选器富集、分光光度法测定羊角铺水源水中痕量亚硝酸盐氮的方法,介绍了试验的注意事项。方法在0μg/L-4.00μg/L范围内线性良好,检出限为0.0002mg/L,RSD为2.0%-4.6%,加标回收率为94.0%-108%。 相似文献
10.
Indoor NO 2 concentrations were measured in the kitchen, the living room and bedroom of 612 houses in two different areas in the Netherlands. In a group of housewives living in these homes, personal exposure to NO 2 was measured. NO 2 concentrations indoors were dependent on the presence or absence of (un)vented gas appliances. Personal NO 2 exposure was only different between the two areas in the group with the lowest indoor concentrations. In this study, it was determined that gas appliances inside the house are the most important factor with respect to NO 2 exposure and that outside NO 2 concentration played a secondary role, except in situations where gas appliances were absent. 相似文献
11.
South Africa has been identified as a source of industrial pollution that is significant at a global scale. This study was designed to provide quantitative information, by direct measurement, across northeastern South Africa, which includes the highly industrialised Mpumalanga Highveld. The specific aim of the study was to evaluate whether or not acidic atmospheric pollution poses a threat to soils, plants and water bodies of South Africa. To address this aim, a network of 37 passive sampling sites was established to measure monthly mean concentrations of near-surface SO 2, NO 2 and ozone. The area covered extended over the northern and eastern interior of South Africa while avoiding sources of local emissions such as towns, mines and highways. The field campaign was conducted between August 2005 and September 2007. Spatial distributions and temporal trends for these pollutant gases were assessed. Critical levels analysis comparisons were made against applicable air quality standards, guidelines and limits to evaluate the potential for adverse atmospheric pollution impacts on regional environments. The assessment indicates that only in the central source area of the South African industrial Highveld are some levels exceeded. In remote areas, including the sensitive forested regions of the Drakensberg escarpment, pollutant concentrations are below the critical thresholds for environmental damage. 相似文献
12.
O(3), NO(2), SO(2), CO and PM(10) concentrations, simultaneously determined for the first time in Belgrade urban area in the autumnal period of 2005, are presented. The obtained results display similar behaviour of SO(2), NO(2), CO, PM(10) opposite from that of O(3). The weekend effect was also investigated showing diminution of average daily concentrations of SO(2), NO(2), PM(10) and CO for 72, 40, 37 and 42% respectively, and increase of the average daily concentration of O(3) for 56%. Influence of meteorological conditions on observed concentration levels was studied, too. The observed influence of wind speed on the O(3) nightly concentration levels was analyzed pointing to the phenomena of O(3) transport during episodic measurements. To make an identification of possible pollution sources and analyse the influence of meteorological parameters on pollution levels, air back trajectories for high level concentrations episodes were calculated and analysed. A multivariate receptor modelling (Principal Component Analysis, Cluster Analysis) has been applied to a set of data in order to determine the contribution of different sources. It was found that the main principal components, extracted from the air pollution data, were related to gasoline combustion, oil combustion and ozone transport. 相似文献
13.
The CO, NO and NO2 concentrations, visibility and air flow velocity were measured using continuous analysers in a long Norwegian road tunnel (7.5 km) with traffic in both directions in April 1994 and 1995. The traffic density was monitored at the same time. The NO2 concentration exceeded Norwegian air quality limits for road tunnels 17% of the time in 1994. The traffic through the tunnel decreased from 1994 to 1995, and the mean NO2 concentration was reduced from 0.73 to 0.22 ppm. The ventilation fan control, based on the CO concentration only, was unsatisfactory and the air flow was sometimes low for hours. Models for NO2 concentration based on CO concentration and absolute air flow velocity were developed and tested. The NO2/NOx ratio showed an increase for NOx levels above 2 ppm; a likely explanation for this phenomenon is NO oxidation by O2. Exposure to high NO2 concentrations may represent a health risk for people with respiratory and cardiac diseases. In long road tunnels with two-way traffic, this study indicates that ventilation fan control based on CO concentration should be adjusted for changes in vehicle CO emission and should be supplemented by air flow monitoring to limit the NO2 concentration. 相似文献
14.
Greenhouse gases are more sampled than ever because of environmental interests. Gas samples are often inserted into vials with gas tight butyl rubber septa before concentration analysis. Little is known on the global transfer property of butyl rubber septa for CO2, N2O and CH4. Sorption kinetics were measured by injecting CO2, N2O or CH4 into glass vials with either one of four butyl rubber septa types and stored during 90 days. CO2 and N2O concentrations decreased during storage depending upon septa type and initial concentration, with the highest linear rate being 0.023 for CO2 and 0.0015 mg L(-3) day(-1) for N2O. When a low concentration was injected, CH4 concentration changes over time were small and did not differ between septa types. Sorption isotherms were measured using nine concentrations and stored during 45 days. CO2 sorption isotherms ranged from 0 to 3.7 x 10(-3) m(3) m(-2) and N2O from 0.3 to 1.4 x 10(-3) m(3) m(-2). Examples of errors associated with the use of these butyl rubber septa are given. 相似文献
15.
Genetically modified crops (GMCs) and climate change have been two ecological issues intensely debated over the years. The search for global solutions to the effects of climate change on agriculture has led to the proposal of GMCs as a tool to reduce the environmental impact of agricultural practices and to improve their efficiency of production. At least 27 countries, all over the world, have cultivated GMCs. The purpose of the present paper is to provide insights about the possible linkages between the cultivated areas and the CO2 emissions in these countries. In addition, the study intends to establish meaningful relationships between attributes related to the particular socio-economic situations and the environmental impacts of GMCs. Some examples are the connection between acreages of GMCs and the status of each country with respect to the Cartagena Protocol on Biosafety, as well as their classification according to the mean income per capita and their CO2 emissions. In order to give the mathematical support to these links, the methodology known as Order Theory was employed. The results show that Paraguay, India, Burkina Faso, Brazil and Pakistan could be the best contributors to the mitigation of the climate change by the reduction of their CO2 emission levels through GMCs. 相似文献
16.
A study of the equivalence to the reference methods of the Radiello samplers for ozone (O(3)) and benzene as well as the membrane-closed Palmes tube (MCPT) for nitrogen dioxide (NO(2)) is presented. These samplers benefit from new model equations capable of estimating their uptake rate. For O(3), the aim here was to demonstrate the equivalence for the reference period of 8 h and 120 microg m(-3), the target value of the 3rd European Daughter Directive. For benzene, the demonstration of equivalence to the annual limit value of 5 microg m(-3) of the 2nd European Daughter Directive was examined. In the case of NO(2), the equivalence to the annual limit value of the 1st European Daughter Directive (40 microg m(-3)) was considered. Results show that the radial sampler for O(3) fails to meet the Data Quality Objective (DQO) for continuous monitoring. However, with an expanded uncertainty of less than 30%, the O(3) diffusive sampler fulfils the DQO for indicative measurements. For benzene, the Radiello sampler exposed for 7 days gave satisfying results showing the ability of the sampler to meet the DQO of the reference method. Nevertheless, the field tests should be complemented by measurements for a wider range of benzene concentrations. In the case of NO(2), all the results of the laboratory and field experiments respected the requirements necessary for the demonstration of equivalence. Overall, these findings thus show that the Radiello sampler and the MCPT are equivalent to the reference methods only for assessment of benzene and NO(2), respectively. 相似文献
17.
The volatile organic pollutants from direct vehicular exhaust were trapped with activated charcoal, desorbed with carbon disulphide and analysed by GC/MS with tert-butyl benzene as an internal standard. A comparative study was made from the exhaust of 1000 cc, 1300 cc, 1600 cc cars, pickup, lorry(diesel), 125 cc and 70 cc motorbikes. The level of pollutants emitted were in the following order, motorbike(petrol) car(petrol) pickup(petrol) lorry(diesel). The range of highest emission (125 cc motorbike) to the lowest emission (lorry(diesel)) was of the order of 102 for benzene, 6×102 for ethyl benzene, 5×102 for toluene and 3×102 for xylenes. Among cars, those fitted with catalytic convertors emitted a lower level of benzene (2 to 3 times) when compared with those without catalytic convertors. Similar studies on the air in air-conditioned buses, non air-conditioned buses and three metres from the edge of the road shows that they have the same pollutant level. The level of these pollutant as compared to those from direct car exhaust are of the order of 102 times less for benzene, xylene and toluene and 103 times less for ethylbenzene. The levels of benzene, toluene, ethylbenzene and xylenes by the road side and in the buses were found to be lower than the exposure limits of ACGIH, OSHA and EH40. 相似文献
18.
用自主研制的采样管开展环境空气中SO2和NO2的被动采样监测.结果表明,被动采样监测结果与自动监测结果高度相关,经回归方程修正后,两者的结果没有显著性差异,被动采样的采样和分析产生的误差得以消除. 相似文献
19.
We present in this paper fifteen years' measurements, from March 1991 to September 2005, of stratospheric NO2 vertical columns measured by a SAOZ zenith-sky visible spectrometer. The instrument spent most of its time at Aberystwyth, Wales, with occasional excursions to other locations. The data have been analysed with the WinDOAS analysis program with low-temperature high-resolution NO2 cross-sections and fitting a slit function to each spectrum. Because of a change in detector in May 1998 there is some uncertainty about the relative changes before and after this date, which are partially constrained by the results of an intercomparison exercise. However, the effect of the Mt Pinatubo aerosol cloud is very evident in the data from 1991-94, with a decrease of 10% in NO2 in the summer of 1992 (the SAOZ was located in Lerwick, Scotland during the winter of 1991-92 and observed very low NO2 values but these cannot be directly compared to the Aberystwyth data). To focus more on interannual and long-term variations in NO2, a seasonal variation comprising an annual and semi-annual component was fitted to the morning and evening twilight separately from 1995 to the present. This fit yielded average NO2 columns of 4.08 x 10(15) cm(-2) and 2.68 x 10(15) cm(-2) for the evening and morning twilight, respectively, with a corresponding annual amplitude of +/-2.08 x 10(15) cm(-2) and +/-1.50 x 10(15) cm(-2). Departures from the fitted curve show a trend of 6% per decade, consistent with that reported elsewhere, for the period 1998-2003, but in the past two years a distinct interannual variation of amplitude of approximately 8% has emerged. 相似文献
20.
Ozone, NO 2, SO 2, CO, PM 10 and meteorological parameters were measured simultaneously during the summer?Cautumn season 2007 in Osijek??the eastern, flat, agricultural part of Croatia. Fourier analysis confirms the existence of variation in ozone volume fractions with periods ranging from the usual semi-daily and daily to 7 and 28 daily cycles. The relationships between O 3 and other variables were modelled in three ways: principal component analysis, multiple linear regression and principal component regression. The results of the principal component analysis detected underlying relationships among ozone concentrations and meteorological variables. An extremely simple meteorological model is suitable for the prediction of ozone levels. The meteorological factors, temperature and cloudiness played a main role in the MLR model ( R 2?=?0.83). The application of the principal component regression approach confirmed that the original variables associated with the valid principal components were meteorological variables ( R 2?=?0.82). 相似文献
|