A diffusion tube survey of NO2 levels in urban areas of the U.K.

A nationwide survey of ambient NO₂ concentrations has been carried out by Warren Spring Laboratory and AEA Technology, Harwell, in urban areas of the U.K. The survey utilised passive diffusion tube samplers, deployed at 363 existing smoke/SO₂ monitoring stations, and ran from July to December 1986.Although undertaken primarily to provide an independent check on the siting of monitoring stations to determine compliance with the European Community NO₂ Directive, the survey provides for the first time a nationwide picture of urban levels of this pollutant. London was found to experience the highest average NO₂ concentrations in the U.K., with these being highest close to busy roads. Concentrations were found to be only moderately higher in winter than in summer.Correlations between measurements of SO₂, smoke and NO₂ were examined. The closest correlation is observed between NO₂ and smoke, indicating traffic to be a dominant source of these pollutants. NO₂ data are also shown to correlate well with disaggregated NO_x emission data for the U.K.     

Stochastic simulation of diurnal variations of CO,NO and NO2 concentrations in occupied residences

A stochastic approach to the problem of incorporating variable emission events in indoor air quality models is proposed. A nonstationary Poisson process is used to account for the occurrence of range-top burner use. The combination of this emission event sequence with a simple one-compartment mass-balance model results in output that qualitatively agrees with measured concentrations in two occupied townhouses. Improved monitoring of stove usage times, gas flow rates and emission factors under field conditions would allow more effective estimation of model input parameters and more accurate prediction of concentration distributions.     

Ethical and legal implications in IVF and prenatal diagnosis in the U.K.

The natural desire for couples to be parents and the medical practitioner's inability to treat most genetic diseases have been responsible for some of the most exciting research into infertility and genetic disorders. This has led in the United Kingdom to the establishment of the Warnock Committee of Inquiry into Human Fertilization and its report in 1984, and to a Review of the guidance on Research Use of Fetuses and Fetal Material published in 1989 and known as the Polkinghorne Report. The Warnock Report, among other ethical issues, considers the most fundamental question which has been debated for thousands of years, namely, What is life and when does it begin? More recently, the report has been responsible for new legislation which imposes ethical and legal restrictions on the scientific and medical community. The Polkinghorne Report recommends a voluntary code of practice which is morally and ethically acceptable within our society. We are also fortunate in the U.K. to have a parliamentary structure which allows debate on such important human issues and is prepared to impose ethical restrictions.     

Benefits and hazards of new crops: oilseed rape in the U.K.

An agroecosystem contains many interralated components. Change within that system or even within larger systems affects these components. The adoption of a new crop, like many other innovations, may therefore lead to other changes. This paper reports on the changes that can occur in production, protection and pollution as a result of farmers adopting new crops. This pattern of events is examined in more detail in a case study of oilseed rape in the U.K.     

NO-CO-CO2-N2体系中若干金属氧化物对NO去除反应的催化作用

采用固定床流动反应装置，考察Ｃｕ２Ｏ、ＣｕＯ、Ｃｒ２Ｏ３、Ｆｅ２Ｏ３、ＭｎＯ２、Ｎｉ２Ｏ３、Ｖ２Ｏ５等金属氧化物对ＮＯＣＯＣＯ２Ｎ２体系中ＮＯ去除反应的催化作用，同时，分析了ＮＯＣＯＣＯ２Ｎ２体系中金属氧化物对ＮＯ去除的作用。研究结果表明，各金属氧化物对ＮＯ去除反应均有不同程度的催化活性，其中Ｆｅ２Ｏ３、Ｎｉ２Ｏ３、ＣｕＯ等对ＮＯ的去除显示出较强的催化作用。金属氧化物存在条件下ＮＯＣＯＣＯ２Ｎ２体系中，ＮＯ去除反应较为复杂，ＮＯ／ＣＯ气相直接反应、低价氧化物对ＮＯ的还原作用、金属氧化物对ＮＯ分解反应的催化作用及金属氧化物对ＮＯ／ＣＯ反应的催化作用等都可能存在。大部分金属氧化物以对ＮＯ／ＣＯ反应的催化作用为主，而Ｎｉ２Ｏ３的预还原试样对ＮＯ的直接分解反应表现了极强的催化活性。     

武汉市1987—2009年城市发展及其驱动力分析

城市发展导致土地资源不合理利用和环境破坏,促使人们对城市发展模式及动力进行分析和研究。运用遥感监测手段,选用长时间序列的Landsat遥感数据,提取了武汉市1987—2009年土地利用数据,通过对比分析居住用地的分布特征和面积,并结合其他土地利用变化数据,完成了武汉市22年来城市发展过程中居住用地特征的对比和分析;另外选取人口、经济、流动人口、城市轨道交通规划和城市圈规划5个因素,完成了武汉市城市发展驱动力分析。结果表明:在城市发展初期人口作为城市发展的主要驱动力,中期城市经济增长为主要因素,后期则是政府规划和引导决定了城市发展的速度和方向。     

Formation of HNO2 on aerosol surfaces during foggy periods in the presence of NO and NO2

A commercial Differential Optical Absorption Spectrometer (DOAS), measuring trace gases absorbing in the u.v./vis region was used for obtaining information on aerosol parameters (e.g. total surface) based on the observed Mie scattering. This procedure allows simultaneous measurements of trace gas concentrations and aerosol parameters within the same air volume. A series of measurements of HNO₂, NO₂, NO, SO₂ and aerosol parameters was performed at Ispra in northern Italy. The observations show a rapid formation of gaseous HNO₂ during foggy episodes and give direct evidence of an important contribution of reactions on wet aerosols to the transformation of tropospheric NO_x into HNO₂.     

A land use regression for predicting NO2 and PM10 concentrations in different seasons in Tianjin region,China

Land use regression (LUR) model was employed to predict the spatial concentration distribution of NO2 and PM10 in the Tianjin region based on the environmental air quality monitoring data. Four multiple linear regression (MLR) equations were established based on the most significant variables for NO2 in heating season (R2 = 0.74), and non-heating season (R2 = 0.61) in the whole study area; and PM10 in heating season (R2 = 0.72), and non-heating season (R2 = 0.49). Maps of spatial concentration distribution for NO2 and PM10 were obtained based on the MLR equations (resolution is 10 km). Intercepts of MLR equations were 0.050 (NO2, heating season), 0.035 (NO2, non-heating season), 0.068 (PM10, heating season), and 0.092 (PM10, non-heating season) in the whole study area. In the central area of Tianjin region, the intercepts were 0.042 (NO2, heating season), 0.043 (NO2, non-heating season), 0.087 (PM10, heating season), and 0.096 (PM10, non-heating season). These intercept values might imply an area’s background concentrations. Predicted result derived from LUR model in the central area was better than that in the whole study area. R2 values increased 0.09 (heating season) and 0.18 (non-heating season) for NO2, and 0.08 (heating season) and 0.04 (non-heating season) for PM10. In terms of R2, LUR model performed more effectively in heating season than non-heating season in the study area and gave a better result for NO2 compared with PM10.     

Modelling and measurement of the dispersion of radioactive emissions from a nuclear fuel fabrication plant in the U.K.

The ground-level air concentrations of supported and total ²³⁴Th were determined over a period of 1 year at four sites in the vicinity of a nuclear fuel fabrication plant in northwest England. Both supported and unsupported ²³⁴Th were found, with mean monthly concentrations of total ²³⁴Th 13 times those observed at a control site 50 km north of the factory. Bulk deposition rates of total ²³⁴Th were found to be 2–3 times the background values. Analysis of mosses revealed a systematic decrease in supported ²³⁴Th concentrations with distance from the factory, with background values reached at a distance of about 1.5 km. Road dust samples showed a similar decrease in supported ²³⁴Th concentrations with distance, but with significant departures from this trend, possibly being evidence for the mechanical transport of contaminated dust from the factory. A Gaussian plume dispersion model was able to predict 85% of the observed air concentrations within a factor of four, despite large uncertainties in some source parameters.     

北京大气中NO、NO2和O3浓度变化的相关性分析

臭氧(O3)是城市污染大气中的首要光化学污染物,其变化规律与氮氧化物(NOx=NO NO2)关系密切.采用49C臭氧分析仪和42CTL氮氧化物分析仪对北京城区O3和NOx浓度进行了连续观测,时间为2004-08～2005-07.结果显示,O3和OX(O3 NO2)浓度在午后15:00左右出现峰值,NOx呈双峰态日变化,在07:00和23:00左右出现峰值.不同季节污染物的浓度变化存在差异,O3和NOx浓度分别在夏季和冬季达到最大.NOx浓度存在100×10-9(体积分数)的"分界点",NOx低浓度时以NO2为主,NOx高浓度时NO占大部分.OX区域贡献和局地贡献存在明显的季节变化,前者主要受区域背景O3的影响,在春季最大,后者主要受局地NOx光化学反应的制约,在夏季最强,同时OX组分呈现显著的昼夜差异.     

The effect of increased energy prices on the viability of organic agricultural systems on arable farms in the U.K.

Parametric programming was used on a mixed-integer linear programming model of a typical U.K. arable farm to examine the impact of increased energy prices on the viability of organic farming systems. It was found that, although input costs were generally lower with the organic system, the net farm revenue was reduced due to decreased income from crop sales. The organic system, therefore, did not enter the optimal solution. Energy costs per ha with the organic system were 25% lower than with a conventional cropping system, although energy costs per £ of output were 25% higher. A doubling of energy prices in the model led to only a small improvement in the competitive position of the organic system. This model would suggest, therefore, that changing energy costs are unlikely to have a significant impact on the competitive position of organic agricultural systems on arable farms in the U.K.     

A land use regression for predicting NO2 and PM10 concentrations in di erent seasons in Tianjin region, China

Land use regression (LUR) model was employed to predict the spatial concentration distribution of NO2 and PM10 in the Tianjin region based on the environmental air quality monitoring data. Four multiple linear regression (MLR) equations were established based on the most significant variables for NO2 in heating season (R2 = 0.74), and non-heating season (R2 = 0.61) in the whole study area; and PM10 in heating season (R2 = 0.72), and non-heating season (R2 = 0.49). Maps of spatial concentration distribution for NO2 and PM10 were obtained based on the MLR equations (resolution is 10 km). Intercepts of MLR equations were 0.050 (NO2, heating season), 0.035 (NO2, non-heating season), 0.068 (PM10, heating season), and 0.092 (PM10, non-heating season) in the whole study area. In the central area of Tianjin region, the intercepts were 0.042 (NO2, heating season), 0.043 (NO2, non-heating season), 0.087 (PM10, heating season), and 0.096 (PM10, non-heating season). These intercept values might imply an area’s background concentrations. Predicted result derived from LUR model in the central area was better than that in the whole study area. R2 values increased 0.09 (heating season) and 0.18 (non-heating season) for NO2, and 0.08 (heating season) and 0.04 (non-heating season) for PM10. In terms of R2, LUR model performed more e ectively in heating season than non-heating season in the study area and gave a better result for NO2 compared with PM10.     

上海市市区、郊区NO2、SO2和PM10的时空变化规律及相关性分析

在对上海市嘉定区大气污染物SO2、NOx和PM10连续1年的观测基础上，结合上海环境状况公报的数据，探讨了市区、郊区大气污染物的空间和时间变化规律。结果表明，2005年中NO2、SO2和PM10的质量浓度在市区和郊区均是冬春两季高，夏秋两季低；NO2、SO2和PM10浓度在市区要高于郊区；郊区大气污染物的月变化幅度要比市区大，市区PM10污染有增加趋势。根据气象条件分析，嘉定区周边工业污染对NO2、SO2和PM10的浓度有贡献，市区NO2、SO2和PM10的质量浓度则与机动车尾气、工业燃煤，建筑扬尘和道路扬尘等诸多因素有关。相关性分析表明，上海市NO2、SO2和PM10相互之间存在比较强的相关性。     

Science-based permitting of geological sequestration of CO2 in brine reservoirs in the U.S.

We present a science-based approach to the regulation and permitting of CO₂ sequestration activities. Any such regulatory scheme should address both operational (or short-term) issues and the long-term goals of geological sequestration of CO₂. In the United States many of the key operational issues, such as permitting injection wells and CO₂ pipelines, are reasonably well addressed in current Federal- and State-based rules and legislation. The long-term, overarching goal of sequestration projects of decreasing the rate of increase in atmospheric concentrations of CO₂ is not addressed by current regulations. We propose a hierarchical approach, in which the State/Federal government is responsible for developing regional assessments that result in broad regions of brine reservoirs being rated as “sequestration ready” (and designated in this paper as general permits). The burden faced by an applicant in permitting an injection site should be considerably less if the general area of the chosen site has been ranked favorably. Such a phased, hierarchical permitting process would be helpful in addressing public and stakeholder concerns related to the impact and safety of geological sequestration operations. It will also build in coordination between neighboring injection sites, where interferences are likely because of the large amount of CO₂ to be injected.     

The near U.V. absorption spectra of several aliphatic aldehydes and ketones at 300 K

Absorption cross-sections are reported for acetaldehyde, propionaldehyde, isobutyraldehyde, n-butyraldehyde, acetone, 2-butanone, 2-pentanone, and 3-pentanone at wavelengths greater than 200 nm, a temperature of 300 K, and a spectral resolution of 0.50 nm. In general, the results are in good agreement with previous measurements of the spectra of these molecules, but are of higher precision than past measurements. For acetaldehyde, propionaldehyde, isobutyraldehyde, and acetone the cross-section results are combined with previous experimental measurements of the primary quantum yield for photolysis to estimate photodissociation rate constants for a representative set of atmospheric conditions. For the other four carbonyl compounds, upper limits for the photodissociation rate constant are calculated assuming a primary quantum yield of unity at all wavelengths. For acetaldehyde, photolysis is slow in comparison with reaction with hydroxyl radical. For the larger aldehydes and for acetone, photolysis and reaction with OH radical take place at comparable rates. For larger ketones, if the quantum yields for photolysis are unity, as assumed in our calculations, the rate of loss of the compounds by photodissociation could be important compared to reaction with hydroxyl radical.     

Interference from HONO in the measurement of ambient air NO2 via photolytic conversion and quantification of NO

The reference method to quantify mixing ratios of the criteria air pollutant nitrogen dioxide (NO₂) is NO-O₃ chemiluminescence (CL), in which mixing ratios of nitric oxide (NO) are measured by sampling ambient air directly, and mixing ratios of NO_x (= sum of NO and NO₂) are measured by converting NO₂ to NO using, for example, heated molybdenum catalyst or, more selectively, photolytic conversion (P-CL). In this work, the nitrous acid (HONO) interference in the measurement of NO₂ by P-CL was investigated. Results with two photolytic NO₂ converters are presented. The first used radiation centered at 395 nm, a wavelength region commonly utilized in P-CL. The second used light at 415 nm, where the overlap with the HONO absorption spectrum and hence its photolysis rate are less. Mixing ratios of NO₂, NO_x and HONO entering and exiting the converters were quantified by Thermal Dissociation Cavity Ring-down Spectroscopy (TD-CRDS). Both converters exhibited high NO₂ conversion efficiency (CF_NO2; > 90%) and partial conversion of HONO. Plots of CF against flow rate were consistent with photolysis frequencies of 4.2 s^-1 and 2.9 s^-1 for NO₂ and 0.25 s^-1 and 0.10 s^?1 for HONO at 395 nm and 415 nm, respectively. CF_HONO was larger than predicted from the overlap of the emission and HONO absorption spectra. The results imply that measurements of NO₂ by P-CL marginally but systematically overestimate true NO₂ concentrations, and that this interference should be considered in environments with high HONO:NO₂ ratios such as the marine boundary layer or in biomass burning plumes.     

美国的环境标准

介绍了美国环境标准的法律地位与作用以及大气环境标准、水环境标准、固体废物处理场标准,并分析了其特点。      

Cytogenetic analysis of chorionic villi for prenatal diagnosis: An ACC collaborative study of U.K. data

A prospective 3-year collaborative study was undertaken in 1987 to collect cytogenetic data from diagnostic chorionic villus samples (CVS) in the U.K. in order to determine the predictive value of the chromosome abnormalities encountered. Twenty-seven laboratories contributed a total number of 7595 cases, of which 97·6 per cent were successful. Excluding single cell anomalies, a total of 480 cytogenetic abnormalities were reported, of which 137 were familial structural rearrangements and 343 were de novo problems. Non-mosaic trisomies of chromosomes 13, 18, and 21 (n=157), non-mosaic sex chromosome abnormalities (n=33), and triploidy (n=6) were all confirmed in cells of fetal origin where follow-up information was available. Of the nine remaining non-mosaics including tetraploidy, trisomies of other autosomes, and extra markers, only a trisomy 16 and a case of a supernumerary marker proved genuine. Eighty-eight cases of mosaicism were reported to the study, of which only nine were confirmed as genuine: two cases involving chromosome 13, one trisomy 18, two examples of extra marker chromosomes, three 45,X, and one 47,XXX. There were no reports of false-negative findings. Presumptive maternal cell contamination was encountered in 39 cases, a detected incidence of 0·5 per cent. Four cases of presumptive ‘vanishing twin’ were recorded: in three of these, direct preparations showed a female karyotype, whereas cultures indicated a male (with male fetuses in two cases). The fourth case was of a female fetus with male and female cells in the CVS cultures. Subtle structural chromosome abnormalities were missed in three instances. Accurate prediction of the fetal karyotype was shown to require detailed knowledge of both the nature and the distribution of abnormal cells in the extra-embryonic tissues. In many cases, this could only be made where results from direct preparations and cultured cells were available. A number of conclusions were reached from these and similar data in the literature regarding the reliability of chromosome findings in CVS.     

微污染水源水中NO2--N的去除

采用生物接触氧化法对北京某水库的微污染水源水进行了去除NO2-—N的试验研究。结果表明,运行期间,生物接触氧化柱(简称生化柱)对NO2-—N的去除率最高可达98%。水温对NO2-—N的去除效果有很大影响,水温越高,生化柱去除NO2-—N的效果越好;在原水水温相同的条件下,原水中NH4+—N浓度越低,生化柱去除NO2-—N的效率越高;原水中NO2-—N浓度越高,生化柱去除NO2-—N的效率越高。