Interpreting Urban Carbon Monoxide Concentrations by Means of a Computerized Blood COHb Model

A practical, inexpensive computer model for estimating the level of blood carboxyhemoglobin (percent COHb) as a function of time for measured carbon monoxide concentrations (ppm CO) was developed from data from published studies on the assimilation of CO into the blood of human subjects. The model was designed to consider more realistically the dynamic characteristics of urban CO concentrations measured continuously at air monitoring stations, and it was applied to a year's CO data measured at the San Jose CA, air monitoring station (8760 hourly values).

The results indicate that the model can be used by local air pollution control agencies to calculate and print out estimated COHb levels alongside continuous CO concentration data. According to the model, the National Ambient Air Quality Standards (NAAQS) for CO sometimes were violated in San Jose without exceeding 2% COHb, as well as the converse: 2% COHb was exceeded without violating the standards. The model's estimated COHb levels also provided an advance warning of impending violation of the 8-hr CO NAAQS, and analysis of the model's response to CO "spikes" suggests that averaging periods as short as 10 or 15 minutes are necessary to preserve completely the dynamic characteristics of ambient CO monitoring data. These findings suggest that the margin of safety included in the current CO NAAQS, would not be the same if the actual time variation of measured CO concentrations is taken into account.     

A Comparison of Filter Types in the Collection and Gravimetric Determination of Airborne Particulate Matter Less than 2.5 Microns (PM25)

ABSTRACT

Five identical, collocated, low-volume samplers were operated to collect airborne particulate matter less than 2.5 microns (PM₂₅). Five commercially available filter types were installed in the samplers to compare the gravimetric determination of PM_2.5 concentrations in the atmosphere. The filters were rotated through the five samplers for two study periods—one in summer and one in winter. The study was performed in Sheridan, WY, in close proximity to a gravimetric laboratory to minimize the introduction of errors associated with sample handling. Rigorous quality assurance procedures were employed throughout the study.Four of the five filter types provided comparable gravimetric determinations of airborne PM_2.5.     

微生物膜法快速测定水中的BOD

利用微生物膜法快速测定水中的BOD,用质控样和标液进行方法准确度和精密度的考察,标准偏差在0.9%～5.2%之间,相对误差≤4.0%,加标回收率为95.5%～103%.与接种稀释法进行对比实验,相对误差在1.5%～10.3%范围内,两种方法测定结果基本一致.     

毛细管柱气相色谱法测定大气污染源氯苯类化合物

建立了毛细管柱-ECD检测器气相色谱测定大气污染源中氯苯类污染物的检测方法,当采样量为30 L时,方法检测限：氯苯0.03μg/m^3、1.2-二氯苯0.10μg/m^3、1.4-二氯苯0.08μg/m^3、1.2.4-三氯苯0.20μg/m^3,加标回收率在78.9%-90.6%之间,相对标准偏差为2.7%-3.3%。方法简单、灵敏、分离度好、检出限低。     

The Identification and Determination of Airborne Particulates By Means of the Ring Oven Technique

The ring oven technique was first introduced as a means for conducting separations and concentrations on filter paper for final spot test analysis. By means of the technique, a complete qualitative scheme of separation and analysis can be made on a single drop of unknown. Recently, the effectiveness of the ring oven as a tool for quantitative analysis has been recognized. The method is particularly attractive for studies of airborne particulates. Samples of airborne particulates can be collected by high volume samplers, tape samplers, electrostatic precipitators, or by other appropriate means. The samples may be put into solution and an aliquot added to filter paper on a ring oven and washed to the ring zone for final identification and estimation. Any necessary separations can normally be carried out during the ring oven operations. A convenient approach for most studies is to collect the samples on tapes and carry out the necessary dissolution, separation, identification, and estimation steps directly on the tape itself. The ring oven methods are usually selective or even specific. The method applies to the microgram to nanogram range and the accuracies are comparable with those obtained by emission spectroscopy, polarography, fluorimetry, and spectrophotometry.     

溶剂萃取法提取电镀污泥浸出液中的铜

研究了N_(510)-煤油-H_2SO_4体系分离电镀污泥氨浸液中的Cu~(2+)的工艺过程,确定萃取铜的最佳工艺参数,以及负铜有机相反萃取较优工艺条件。研究结果表明,以N_(510)为萃取剂,经四级逆流萃取,铜的萃取效率达99％,共存的Ni~(2+)和Zn~(2+)损失量接近0,不影响后续有价金属的回收。铜在工艺过程中以铜盐CuSO_4·5H_2O或电解纯铜的形式得以回收,具有较高的经济效益。     

Determination of Source Contributions to Ambient Volatile Organic Compound Concentrations in Berlin

ABSTRACT

During three measuring campaigns in June, July, and August 1996, volatile organic compound (VOC) concentrations were measured at a rural background site, a city residential site, and a street site in Berlin. In addition, samples were taken near relevant sources of VOCs. The meaurements covered the volatile hydrocarbons in the range C₁-C₁₄ and included aldehydes and ketones. Samples were taken at four characteristic periods of 2 hr/day: during the night, during the early morning rush hour, at midday, and during the evening rush hour. An assessment of the contribution of emission categories to the observed concentrations was made with the chemical mass balance (CMB) modelling technique.

The VOC concentrations at the residential area and at the street site in the inner city were, respectively, a factor of 3 and 7 above the background concentration. Traffic exhaust contributed approximately 80-90% of the non-methane hydrocarbon (NMHC) concentration in the inner city and approximately 60% at the background area. Evaporative losses of motor fuel are estimated to account for approximately 7% at all sites. Natural gas leakage also contributed significantly to the observed VOC concentrations: in the inner city approximately 510% and at the background area approximately 30%. The measurements also showed a contribution of smaller sources, such as dry cleaning, use of solvents, and bio-genic emissions. However, the contribution of these sources to the total observed concentrations at the sites is estimated to be very small.     

Quantitative Determination of Gaseous Nitrogen Dioxide Concentrations over Long Path Lengths by Selective Absorption of Argon Ion Laser Emission

An argon ion laser emits several laser lines In the visible region of the optical spectrum. The absorption coefficients of N0₂ at these laser emissions were measured in a multiple pass absorption cell. A differential technique, in which the ratio of the transmitted intensities of the argon laser emissions is measured, is described to determine the concentration of N0₂ in a polluted atmosphere over path lengths of several kilometers. Measurement of ratios eliminates interferences from particle scattering and thermal index gradients. Evaluation of the data taken in the 48 meter multipass cell indicates that concentrations of N0₂ less than one part per million could be determined in a 1 km optical path.     

过滤/厌氧/膜生物反应器工艺处理井冈霉素废水

针对生化性较好、COD和SS等污染物浓度极高、含有抗菌素的井冈霉素废水,在场地受限的情况下,采用过滤/厌氧/膜生物反应器工艺处理该废水.结果表明,该工艺流程简洁,操作简单、运行稳定;在进水COD、BOD5和SS分别为34 100、11 900、9 190mg/L的条件下.去除率均在99%以上.出水水质达到<污水综合排放标准>(GB 8978-1996)中的一级标准.     

A Combustion Method for the Determination of Solvent Vapors at Low Concentrations in Air

The nitrogen-containing products of smog chamber reactions have been the subject of much controversy. Concern has arisen over nitrogen products because of the almost universally poor nitrogen balance reported for irradiated mixtures of hydrocarbons and nitrogen oxides. Some possible nitrogen-containing products, such as molecular nitrogen, nitrous oxide, and nitroolefins have been investigated and shown to be unimportant. The nitrogen products most often measured are peroxyacetyl nitrate and residual nitrogen dioxide. These two products rarely comprise more than 70% of the initial nitrogen at the end of an experiment, and often account for less than 50%. Previous experiments in which total nitrate was determined in the gas phase and on the vessel walls at the end of irradiation have shown very good nitrogen balances. The assumption has been made that the nitrate arises from nitric acid formed on the walls by adsorbed N₂O₅.

In the work reported here, all major nitrogen-containing compounds have been monitored continuously for the first time. Nitric oxide and nitrogen dioxide have been monitored by chemilumines-cence and automated Saltzman techniques. Methyl, ethyl, and peroxyacetyl nitrate have been determined by gas chromatogra-phy. Two methods, one continuous and one integrated, have been specially developed to measure nitric acid both in the smog chambers and in the atmosphere. Continuous determination of these compounds yields good nitrogen balances throughout the irradiations.

Profiles of the nitrogen-containing species from irradiated HC/ NO_x mixtures are discussed in terms of nitrogen products and nitrogen balance. Differences in product distribution for different hydrocarbon systems are also considered. Using rate information from the nitrogen compound profiles, important reactions leading to nitrogen-containing products are identified. Interference with the chemiluminescent technique by HON0₂, PAN, and C₂H₅ONO₂ is discussed.     

Concentrations and speciation of arsenic in groundwater polluted by warfare agents

Groundwater polluted with phenylarsenicals from former warfare agent deposits and their metabolites was investigated with respect to the behavior of relevant arsenic species. Depth profiles at the estimated source and at about 1 km downgradient from the source zone were sampled. The source zone is characterized by high total arsenic concentrations up to 16 mg L⁻¹ and is dominated by organic arsenic compounds. The concentrations in the downgradient region are much lower (up to 400 μg L⁻¹) and show a high proportion of inorganic arsenic species. Iron precipitation seems to be an effective mechanism to prevent dispersion of inorganic arsenic as well as phenylarsonic acid. Reductive conditions were observed in the deeper zone with predominant occurrence of trivalent arsenic species. The inorganic species are in redox equilibrium, whereas the phenylarsenic compounds have variable proportions. Methylphenylarsinic acid was identified in groundwater in traces which indicates microbial degradation activity.     

The Law of Federal Air Pollution Control

The Clean Air Act, while recognizing the primary responsibility of states and local governments for the prevention and control of air pollution, provides authority for federal initiative and action to prevent and to abate air pollution which “endangers the health or welfare of any persons.” The applicable statutory procedures and the scope of federal authority are analyzed and discussed.     

The Detection and Estimation of Part Per Billion Concentrations of Hydrocarbons

The addition of a freeze-out step in liquid nitrogen prior to analysis by gas chromatography with flame ionization detection permits the accurate determination of C₂ and higher hydrocarbons in the part per billion (ppb) range. Concentrations of C₂ and higher hydrocarbons have been measured in commercial cylinders of nitrogen, helium and hydrogen. Using a 150 ml sample of gas, recovery of ppb concentrations is 95 to 100 percent.     

乙酰丙酮光度法测定甲醛方法的改进

用乙酰丙酮溶液将CODcr反应管制成标准反应管,CODcr消解器加热回流30min,DR／2010分光光度计比色测定甲醛含量。方法精密度、准确度满足甲醛测定的分析要求。     

水中佳乐麝香的固相微萃取-气质联机测定方法

采用聚二甲基硅氧烷膜厚100μm的纤维萃取设备,阐述了测定水中HHCB的固相微萃取-气质联机的检测方法。研究发现,对于水中的HHCB来说,温度控制在35℃,萃取时间为40 min,pH值为7.0,可实现HHCB的有效萃取,水中的离子对萃取效率的干扰较小。使用该方法测得上海龙华污水厂原水中HHCB浓度为286 ng/L,虹口区泗塘河水中HHCB浓度低于检测下限。     

The New Standard Environmental Inventory Questionnaire for Estimation of Indoor Concentrations

Several investigators have developed indoor air quality questionnaires for use in field studies. The approach used in many of them have numerous features in common, but most of them are unique in their content (wording, format, item selection). It is thought that indoor air quality research could be greatly advanced if the primary or fundamental questions and instruments could be consolidated. The use of a basic set of "standard" questions would permit intercomparison of results from different research studies. It is generally agreed that environmental inventory questionnaires (EIQ) help to classify, at least in screening, relative concentration estimates, which precede exposure estimation. Thus, such instruments are not equivalent to monitoring for exposure assessment. However, data linkage and mega data bases are important for some comparative analyses of exposure assessment and exposure-response relationships. Standard instruments such as the EIQ are useful as a screening device to precede other tests to allow identification of potentially high exposure situations. They can also amplify information from other tests. General usage of standard questionnaires and protocols can lead to cumulative improvements in data collection, specificity and effectiveness. This has been the rationale for the present efforts by investigators to form a standardized environmental inventory questionnaire, under the auspices of the U.S. Environmental Protection Agency (EPA), Gas Research Institute (GRI), and Electric Power Research Institute (EPRI).     

应用选择器抑制污泥膨胀的20年实践

选择器是在控制丝状菌膨胀实践中孕育而生。丝状菌一般在基质浓度较低的条件下生长，基质浓度较高时菌胶团将要代替丝状菌。根据这一理论，选择器在２０年间逐渐地被开发出来。本文列举了一些成功例子的设计参数和具体结构，并指出了选择器的局限性，即它不能解决所有由丝状菌引起的问题。