Standardization of Methods For Measurement of Air Pollutants

Currently available compilations of methods of air analysis are listed. Collaborative testing is urgently needed to reconcile differences and to demonstrate the accuracy of these methods. The Analytical Methods Evaluation Service of the National Center for Air Pollution Control conducted a survey of the instruments and manual methods of analysis in use. Responses are tabulated from about 80 laboratories, in 28 states and 3 foreign countries. Sulfur dioxide was the most widely measured pollutant. The first collaborative study organized by the Analytical Methods Evaluation Service is described. The purpose was to evaluate the permeation tube technique as a primary standard method for generating known sulfur dioxide concentrations for instrument calibration and methods testing. Although a good beginning has been made, the testing of methods for measuring air pollutants has barely begun.     

A Viable System of Biological Indicators For Monitoring Air Pollutants

An air pollution monitoring biological indicator (AMBI) system for ambient ozone was tested in the South Coast Air Basin of California during the 1972 fall growing season. The basic unit or AMBI station was an inexpensive, portable plant station which operated independent of power sources. Reliability of these units was excellent as only three instances of missing data were observed from 330 possibilities. A photo-reference system of ozone injury evaluation utilizing direct comparisons of injured leaves with reference photographs was successful in standardizing assessments of ozone injury. Average weekly injury indices for field locations were correlated with average weekly ozone dosages and were found to be significant at the .01 level.     

Gas Cleaning in a Wetted Butterfly Valve

An attempt was made to demonslrate the utility of a wetted butterfly valve for cleaning flue gases from industrial wastes. Butterfly valves are extensively in use to control the gas pressures in various processes. A small pilot plant with a maximum airflow rate of 400 cfm and water flow rate of 4 gpm was constructed to provide the desired testing conditions. The results indicate that for a pressure drop greater than 30 in. water a collection efficiency of greater than 95% for submicron particles can be obtained. For particles larger than 1.7;u diameter efficiencies of greater than 99% were obtained. The exceptional suitability of wet butterfly valves for gas cleaning is demonstrated by the flexibility to adjust to large variations of gas and liquid flow rates.     

Wet vs Dry Gas Cleaning In the Steel Industry

Deciding whether the gas should be cleaned by a “dry” system or a “wet” system requires a full consideration of all factors of which the capital cost is only one. Anticipating the various problems which might be expected and designing adequate measures for each calls for major engineering effort,but onlythen can a best choice be made. The principles which govern the above are illustrated by a typical selection of gas cleaning equipment to be used as part of a BOF steel making installation. Two entirely different gas cleaning systems are presently in BOF service in North America. Both will do an excellent job if properly designed. Either system will cost in excess of $2,000,000 and will require careful control and large amounts of electrical power. One system, the dry electrostatic precipitator, requires humidification of the gas; protection against explosions; elaborate electrical controls, insulators, etc.; and a rugged handling system for the bone dry dust collected. The other system, wet washing with water, Is easier to control but uses large quantities of water and electric power. As in the case of the “dry” system, handling the dirt collected is a difficult problem requiring careful study and choice of equipment. In either case the dust may be discarded or reused, but it must be handled with care lest it become an air or stream pollution problem all over again.     

The Cost of Stack Gas Cleaning in New York State

A cost estimating methodology has been applied to an emission point inventory to estimate the capital and operating costs of stack gas cleaning in the manufacturing sector of New York State. The study represents the first major attempt to estimate control costs on a source by source basis for a large region. The various control cost components are presented for each of the twenty manufacturing industry groups and the usefulness of the estimates for an abatement planning model is outlined.

In recent years a number of heroic efforts have been made to estimate the cost of air pollution abatement on a national or regional basis. Unfortunately, these studies have relied almost entirely upon emission factors, cost engineering functions, pilot plant operations, and average or ideal firms, because of the paucity of primary data.^1-6

In the estimates of capital and operating costs presented below, an attempt has been made to improve on previous research by making extensive use of primary data. The data were taken from an emission inventory of over 20,000 sources of air contamination in New York State. A cost estimating methodology was applied to engineering parameters of existing control operations on a source by source basis. The results have been aggregated to the two-digit SIC level.     

Variation of Different Pollutants in the Atmosphere of Mexico City

The first regional warning system was developed by the New York-New Jersey Cooperative Committee on Air Pollution and was put into operation in 1964. In 1967, new criteria were adopted based on recommendations of a workshop sponsored by City College of New York at the request of State agencies. With the passage of time, it has been recognized that the criteria necessary to call an alert required updating and strengthening. In recognition of this, the Commission sponsored a workshop of government officials to evaluate the criteria and levels of the sulfur dioxide, carbon monoxide, and particulate parameters used in the system and to consider the addition of other parameters.     

Numerical Modeling of the Transport Diffusion and Deposition of Pollutants For Regions and Extended Scales

There is an emerging need to develop understanding and predictive capability for the transport, diffusion, and deposition of pollutants on regional and extended spatial scales. Some recent developments in the numerical simulation of pollutant transport and diffusion are reviewed and summarized herein, including case studies of model validation whenever’available. The efforts reported include: (a) the development and verification of a Lagrangian large-cloud diffusion code for intermediate to extended scales; (b) a hybrid Lagrangian-Eulerian transport-diffusion code for simulating pollutant distributions in transient stratified shear flow; (c) a meteorological submodel for determining a mass-consistent wind field on a regional scale suitable as input to a regional air pollution model; and (d) the development and initial verification of a multi-box regional air pollution model for the San Francisco Bay Area utilizing a mass-consistent wind field submodel.     

The Stack Height Requirements Implicit In the Federal Standards of Performance For New Stationary Sources

The promulgation of Federal standards of performance for certain classes of new stationary sources requires that such sources have minimum stack heights to meet also the requirements of national air quality standards. The determination of minimum stack height is complicated by the fact that the performance and air quality standards are stated on different averaging time bases; that the extent of preemption of the assimilative capacity of the air by any individual source will vary among jurisdictions and, in some cases, among different geographic areas of a single jurisdiction; and that some new sources will be designed to emit appreciably less than the performance standard requirement. However, these complications can be resolved and equations and charts prepared from which minimum stack height can be selected.     

Gas Cleaning Systems for the High Temperature,High Pressure Fluidized Bed Coal Combustor

The high temperature, high pressure fluidized bed coal combustor concept is intended to deliver a low dust content combustion gas at 1600°F and 11 atmospheres to a gas turbine for electricity generation. The perceived advantages of the system are 1) 15-20% increase in fuel efficiency and 2) flue gas desulfurization by adding crushed limestone to the fluidized bed combustor. A major R & D effort, supported by DOE, EPA, EPRI, and others, was undertaken to identify one or more gas cleaning systems of commercial size capable of 1) meeting EPA’s new source performance standards for coal burning power plants and 2) operating reliably under the severe environmental conditions specified. The principal gas cleaning systems that have been investigated for this service include: ceramic cleanable cloth filters, granular bed filters, rigid, porous ceramic structures, and electrostatic precipitators. Some of the fly ash collectors have been operated up to pilot scale size under realistic conditions. In spite of several years of intensive effort and many millions of dollars expended, production of a commercial unit has not been realized. A major content of this paper is a review of the accomplishments and failures of each of the fly ash collector concepts and a series of recommendations to guide future R & D efforts.     

Polychlorinated Biphenyl Recovery Efficiency from Stack Gas and Ambient Air

Polychlorinated biphenyls (PCBs) are now recognized as presenting a severe environmental hazard because of their toxicity and persistence in the environment. High temperature combustion has been shown to be an effective method for destroying these compounds.¹ Unfortunately, few facilities are available for their destruction. As part of a feasibility study to convert a liquid-waste incinerator designed for waste fuel to a PCB waste, the sampling efficiency of toluene filled fritted impingers and Chromosorb 102 filled tubes was evaluated.     

Design and Verification of a Programmable Gas Dispensing System for Exposing Plants to Dynamic Concentrations of Air Pollutants

Abstract

Landfills represent a source of distributed emissions source over an irregular and heterogeneous surface. In the method termed “Other Test Method-10” (OTM-10), the U.S. Environmental Protection Agency (EPA) has proposed a method to quantify emissions from such sources by the use of vertical radial plume mapping (VRPM) techniques combined with measurement of wind speed to determine the average emission flux per unit area per time from nonpoint sources. In such application, the VRPM is used as a tool to estimate the mass of the gas of interest crossing a vertical plane. This estimation is done by fitting the field-measured concentration spatial data to a Gaussian or some other distribution to define a plume crossing the vertical plane. When this technique is applied to landfill surfaces, the VRPM plane may be within the emitting source area itself. The objective of this study was to investigate uncertainties associated with using OTM-10 for landfills. The spatial variability of emission in the emitting domain can lead to uncertainties of –34 to 190% in the measured flux value when idealistic scenarios were simulated. The level of uncertainty might be higher when the number and locations of emitting sources are not known (typical field conditions). The level of uncertainty can be reduced by improving the layout of the VRPM plane in the field in accordance with an initial survey of the emission patterns. The change in wind direction during an OTM-10 testing setup can introduce an uncertainty of 20% of the measured flux value. This study also provides estimates of the area contributing to flux (ACF) to be used in conjunction with OTM-10 procedures. The estimate of ACF is a function of the atmospheric stability class and has an uncertainty of 10–30%.     

A Filter Test Method For Rapid Weight Distribution Of Dust in Gas Streams To Evaluate Dust Collectors

The purpose of this paper is to describe a simple gravimetric test method that was used as a field tool to diagnose variations and malfunctions in dust collector performance. This method is not considered a replacement for accepted standard test methods for stacks.^1,2,3 Nevertheless, the reproducibility, ease, and value of this short term monitor test method over a two year period, covering over 1000 tests suggest that this method may be used effectively in the field.

The article published below is a condensed version of a paper (67-117) presented at 1967 Annual Meeting.     

Characterization of Solid-Phase Microextraction and Gas Chromatography for the Analysis of Gasoline Tracers in Different Microenvironments

Abstract

Gasoline tracers were collected on solid-phase microextraction (SPME) fibers and analyzed by capillary gas chromatography with photoionization detector (GC/PID). This was part of a larger study to quantify personal exposure to motor vehicle gasoline evaporative and combustive emissions in high-end exposure microenvironments (MEs). The SPME fiber selected for this application was a 75-µm carboxen/polydimethylsiloxane. Sequential 10-min samples were collected for measurement of benzene, toluene, ethylbenzene, and ortho-, meta-, and para-xylene in different MEs in Atlanta, GA, in summer 2002 and Reno, NV, in spring 2003. Field calibrations were performed with certified gas standards in 1-L Tedlar bags for varying concentrations and exposure times. SPME detection limits were ～0.2 ppbv with a precision of 3–17% and accuracy of 30%. A dynamic system was designed for temperature and relative humidity calibrations, with corrections for the effects of these variables performed when necessary. SPME data compared satisfactorily with integrated canister samples, continuous PID, and field portable mass spectrometer data.