Continuous Emission Monitoring: Objectives and Requirements

Regulations were recently proposed by the Environmental Protection Agency which, when promulgated, will require existing and new sources within certain specified source categories to install, operate, and maintain continuous emission monitoring systems. Major comments received on these proposed regulations are discussed as are the overall benefits that can be derived from the utilization of continuous emission monitoring systems.     

Boundary Layer Emission Monitoring

A new methodology is described for determining the atmospheric emission rate of pollutants from large heterogeneous area sources, such as hazardous waste sites. The procedure hinges upon measuring average pollutant concentrations, at three or more different elevations, while traversing the plume downwind of the area source. A helium-filled tethersonde balloon is used to elevate the sampling lines to their appropriate height. During plume traversing the sampling rate is adjusted to be proportional to the sine of the angle between the wind vector and the direction of the traverse path. The average concentrations are corrected for any upwind, background concentration and then used to derive an average vertical concentration profile. This profile Is numerically integrated, with the wind velocity profile, over the pollutant boundary layer to yield the area source emission rate. The methodology was tested on several large industrial effluent lagoons and proved to be easy to use, robust, and precise.     

江苏省火电厂烟气排放连续监测系统运行现状及对策建议

简要介绍了江苏省火电厂已安装的烟气排放连续监测系统（CEMS）的现状,分析了CEMS运行中存在的问题,对CEMS的运行、管理和监督,提出了对策建议。     

Continuous Monitoring for Sulfur Dioxide at A Utility Boiler Equipped with a Limestone Scrubber

The results of a 30-day sulfur dioxide monitoring program conducted at a utility boiler equipped with a limestone scrubber are presented. Program objectives were twofold: to demonstrate the reliable use of continuous monitoring equipment for determining scrubber performance and to support the proposed New Source Performance Standards (NSPS) published in the September 19, 1978, Federal Register. In general, continuous monitoring equipment is reliable as a source surveillance method. Results of the data collected indicate that the test site monitored was capable of performing under the guidelines of the proposed NSPS, and were incorporated in the final NSPS promulgated on June 11, 1979.     

空气自动监测站的防雷措施

介绍了雷电对空气自动监测站是如何造成危害的，阐述了雷电侵入空气自动监测站的途径及防止雷击的办法。     

Continuous Monitoring of FGD Wet Scrubber Corrosion

This article describes an electrochemical corrosion monitoring system developed in England that offers utilities the capability of continuously measuring power plant corrosion activity for a wide range of operating conditions.     

The effects of scrubber installation at the Navajo Generating Station on particulate sulfur and visibility levels in the Grand Canyon

Grand Canyon National Park (GCNP) is a mandatory Class I federal area that is afforded visibility protection under the Federal Clean Air Act. In this paper, we have examined the effects on visibility and particulate sulfur (Sp) at GCNP as a result of reducing sulfur dioxide (SO2) emissions by 90% from the Navajo Generating Station (NGS). Scrubbers were retrofitted to each of the three units at NGS during 1997, 1998, and 1999. The Inter-agency Monitoring of Protected Visual Environments aerosol network database affords us an opportunity to examine trends in Sp and extinction both prescrubber and postscrubber. The NGS impacts GCNP primarily during the winter (December to February). During winter, at times, there are fogs, stratus, and high-relative humidity in the Grand Canyon. When the NGS plume interacts with these fogs and stratus, rapid conversion of SO2 to Sp can occur. A variety of analytical techniques were used, including cumulative frequency plots of Sp and extinction, and chemical mass balance and tracer source apportionment analysis. We also deployed P value statistical analysis of "extreme" Sp values. Before scrubbers were installed, values of Sp approaching 2 microg/m3 were occasionally observed. Because scrubbers have been installed, high levels of Sp have been markedly reduced. Statistical P value analysis suggests that these reductions were significant. Furthermore, we have also observed that Sp has been reduced throughout the cumulative frequency curve during winter by approximately 33% since scrubbers were installed. By contrast, during summer when the NGS impact on the Canyon is minimal, there has been only a relatively small decrease in Sp.     

基层环境监测站仪器期间核查存在的问题及改进措施

基层环境监测站承担着大量监测数据来源的责任,监测数据的质量不容忽视,但基层环境监测站普遍存在对仪器期间核查忽视的问题,严重影响数据质量的可靠程度,所以应根据仪器的性能和使用情况,在规定的时间间隔内,使用相应的核查方法,对仪器进行期间核查,及时预防和发现不合格的仪器并避免误用,保证监测结果持续的准确性、有效性,以维护环境监测站和客户的权益。     

Current Technology for Continuous Monitoring of Gaseous Emissions

The purpose of this paper is to present a discussion of the latest developments in continuous gaseous emissions measurement. Subject areas include extractive and in-situ measurement. An exhaustive discussion of all instrumental methods currently available for use is neither appropriate nor productive in that several reviews have already been published in this area. Current needs for the development of new instrumentation in support of pending EPA regulations will be noted.     

Current Technology for Continuous Monitoring of Particulate Emissions

Particulate matter is characterized by its physical and chemical properties. Federal and state emission standards identify two important physical properties, opacity (visible emissions) and particulate mass concentration. In addition, particle size and particle composition are characteristics that play a significant role in the assessment of health effects, visibility, and control strategy. Systems to monitor these particle characteristics are in various stages of development. Opacity monitors have the longest history of commercial availability and of applicability to various source emissions. Particulate mass monitors have a short history as commercially available systems and are under evaluation in various source applications. Particle size monitors are mainly in the advanced prototype development stage undergoing evaluation. Particle composition monitors are in the early stages of development as research prototypes. Real time size monitoring systems will eventually be wedded to real time particle composition analyzers to give a monitoring system for particle size distributions of chemical constituents.     

The Value of Continuous Monitoring to the User

Potential benefits of a continuous monitoring program are presented in the form of questions that can be asked in connection with the information gained from the program. These questions are:

1. Are there process problems of which we are unaware?

2. Will this information be useful in the design of the next plant?

3. Can the information be used for improved process control?

4. Are we losing valuable material?

5. Can we use this information to modify our process for reduced pollution?     

日本核电站的环境放射线观测局

日本是个核能发达的国家，全国有52座核电站。各个核电站均设有对周围环境放射性监测的观测局和实验室采样分析，在核电使用的安全性、应急制度、对公众的透明度等方面都具有值得借鉴的地方。     

扬中市环境监测站实验室认可中的质量保证

介绍了扬中市环境监测站在创建实验室认可的过程中，将环境监测全过程的质量保证措施纳入质量体系文件，并通过检查实施情况，实现对环境监测全过程的质量管理。     

基层环境监测站环境质量综合分析中存在的问题及对策

从环境监测为环境管理服务的职能入手,系统分析了基层环境监测站的环境质量综合分析工作现状,针对实际工作中存在的问题,提出了提高环境质量综合分析水平的对策建议。     

Continuous Monitoring of Methane and Other Hydrocarbons In Urban Atmospheres

Continuous measurements of total hydrocarbons (and other organic substances) and of methane were made in Cincinnati and Los Angeles for three-month periods. Some of the measurements were made during episodes of photochemical air pollution. Two instruments, one for measurement of total hydrocarbons and the other for methane, were operated in parallel. Both incorporated flame ionization detectors having greater sensitivity than commercial flame ionization instruments. The flame ionization analysis for methane was made specific by use of an adsorbent carbon column preceding the analyzer to retain all organic substances except methane. Subtracting the methane concentration values from those for total hydrocarbons gave nonmethane hydrocarbon concentrations. The data showed diurnal patterns of concentrations of methane and nonmethane hydrocarbons in the atmosphere. Average hourly values for methane were strikingly similar in Los Angeles and in Cincinnati (2.6 and 2.4 ppm, respectively); those for nonmethane hydrocarbons were four times as high in Los Angeles (3.0 and 0.8 ppm, respectively). A bimodal frequency distribution pattern of the concentrations suggested that atmospheric ventilation was either good or poor, with less than a random amount of time in intermediate stages. The width of the methane frequency distribution peak was about half the width of that for nonmethane hydrocarbons, indicating a different and more constant source for the former.     

Evaluation of Continuous Performance Monitoring Techniques for Hazardous Waste Incinerators

This paper discusses monitoring the waste destruction efficiency of hazardous waste incinerators. The particular problem is to ensure that incinerators do not release, without detection, significant quantities of waste as a result of operating fluctuations or equipment degradation. To detect these conditions, continuous, automated, and real-time source monitoring is required. Detection of degraded performance by monitoring and measuring waste compounds directly is not presently possible on a continuous basis. An alternative is to use commercially available continuous monitors to measure combustion intermediates (e.g., CO or hydrocarbons) and thereby infer waste destruction efficiency. Required, however, is a correlation between the emission of intermediates and the emission of waste. In this paper, the response of a number of these continuous monitors is compared with waste destruction efficiency measurements from a laboratory scale, liquid-spray incinerator operated on fuel oil doped with model waste compounds: benzene, chlorobenzene, acrylonitrile, and chloroform. Total hydrocarbon and CH₄ measurements are found to vary with waste emission in a nearly linear manner; however, a substantial increase in CO emission occurs before a significant amount of waste is released. These results suggest that CO may serve as an indicator of the approach of waste release, while total hydrocarbons may provide an indicator of immediate waste release.     

Preparation and Use of Spatially and Temporally Resolved Emission Inventories in the San Francisco Bay Region

Three regional agencies recently prepared an Air Quality Maintenance Plan for the San Francisco Bay Area oxidant problem. An Eulerian, photochemical model, LIRAQ, provided the technical basis for the plan recommendations. A major LIRAQ input is an emission inventory accurately resolved to one kilometer and one hour increments. The cooperating agencies prepared such inventories, covering 20,000 sq km, for one base and two future years. Several manual and computer-assisted techniques were developed to utilize a variety of independent data bases. Population, land use, employment and transportation data were oganized into a common system of coordinates and units to produce the needed spatial input. Estimates of hourly variation were made by source category based on production rates, fuel use, traffic patterns, flight schedules, and other factors. The result was a series of consistent, detailed inventories which provide a powerful air quality modeling and planning tool. The detail is attained at considerable expense, but the cost is easily justifiable when compared to implementation costs for control strategies.     

常温下连续流短程硝化反硝化研究

常温(26～30℃)下应用连续流短程硝化反硝化工艺处理模拟城市生活污水,对连续流短程硝化反硝化污泥的运行参数进行了研究.结果表明,在常温、进水NH4 -N为50 mg/L、曝气区pH为7.5～8.0、曝气量为0.3 L/min、曝气区水力停留时间为4 h的条件下,NO2- -N/(NO3- -N NO2- -N)达0.677,TN去除率为35%左右;在上述条件下,无需调节曝气区pH,选择前置反硝化区与曝气区的体积比为1:2、前置反硝化区水力停留时间为2 h、回流比为2:1时,连续流短程硝化反硝化工艺的TN去除率达88.9%,COD去除率达92.7%;pH的变化规律正确反映了系统运行状况,可作为系统运行的实时控制参数.     

Using Continuous PM2.5 Monitoring Data to Report an Air Quality Index

Abstract

As stated in 40 CFR 58, Appendix G (2000), statistical linear regression models can be applied to relate PM_2.5 continuous monitoring (CM) measurements with federal reference method (FRM) measurements, collocated or otherwise, for the purpose of reporting the air quality index (AQI). The CM measurements can then be transformed via the model to remove any bias relative to FRM measurements. The resulting FRM-like modeled measurements may be used to provide more timely reporting of a metropolitan statistical area’s (MSA’s) AQI.¹ Of considerable importance is the quality of the model used to relate the CM and FRM measurements. The use of a poor model could result in misleading AQI reporting in the form of incorrectly claiming either good or bad air quality.

This paper describes a measure of adequacy for deciding whether a statistical linear regression model that relates FRM and continuous PM_2.5 measurements is sufficient for use in AQI reporting. The approach is the U.S. Environmental Protection Agency’s (EPA’s) data quality objectives (DQO) process, a seven-step strategic planning approach to determine the most appropriate data type, quality, quantity, and synthesis for a given activity.² The chosen measure of model adequacy is r², the square of the correlation coefficient between FRM measurements and their modeled counterparts. The paper concludes by developing regression models that meet this desired level of adequacy for the MSAs of Greensboro/Winston-Salem/High Point, NC; and Davenport/Moline/Rock Island, IA/IL. In both cases, a log transformation of the data appeared most appropriate. For the data from the Greens-boro/Winston-Salem/High Point MSA, a simple linear regression model of the FRM and CM measurements had an r² of 0.96, based on 227 paired observations. For the data from the Davenport/Moline/Rock Island MSA, due to seasonal differences between CM and FRM measurements, the simple linear regression model had to be expanded to include a temperature dependency, resulting in an r² of 0.86, based on 214 paired observations.