Evaluation of Selected Gaseous Halocarbons for Use in source Test Performance Audits

A repository of 38 gaseous organic compounds in compressed gas cylinders has been established by EPA. This repository was established to provide standards for source test performance audits, that is, quantitative quality assurance tests. Among these compounds are ten halogenated organic species, which are the focus of this paper.

Stability studies of all ten compounds have been performed to determine the feasibility of using them as performance audit standards. Results indicate that all of the halocarbons tested are adequately stable to be used as reliable audit standards.

Subsequent to completion of stability studies, four of the ten halocarbons were used in source test performance audits. Results are available at this time for two of the four compounds; the results show agreement within 10% of the concentrations previously established by Research Triangle Institute.     

Testing and Commercialization of Byproduct Dibasic cids as Buffer Additives for Limestone Flue Gas esulfurization Systems

Pilot plant (0.1 MW) tests and utility boiler full scale demonstration (194 MW) of byproduct organic dibasic acids (DBA) as buffer additives to limestone scrubbers have shown performance improvements equivalent to those achieved by the addition of pure adipic acid. Both SO₂ removal efficiency and limestone utilization increased, and no significant operating problems were observed with three of the four DBA tested. Chemical and biological evaluations of scrubber samples taken during the DBA testing indicated no detectable tOxicity or mutagenicity, and no significant environmental impact is expected as a result of DBA addition. Economic estimates indicate that substitution of DBA for pure adipic acid as a buffer additive will result in additive cost savings of 30 % or greater.     

A Simple Methodology for the Determination of Back Trajectories

Abstract

This study comprehensively characterizes hourly fine particulate matter (PM_2.5) concentrations measured via a tapered element oscillating microbalance (TEOM), β-gauge, and nephelometer from four different monitoring sites in U.S. Environment Protection Agency (EPA) Region 5 (in U.S. states Illinois, Michigan, and Wisconsin) and compares them to the Federal Reference Method (FRM). Hourly characterization uses time series and autocorrelation. Hourly data are compared with FRM by averaging across 24-hr sampling periods and modeling against respective daily FRM concentrations. Modeling uses traditional two-variable linear least-squares regression as well as innovative nonlinear regression involving additional meteorological variables such as temperature and humidity. The TEOM shows a relationship with season and temperature, linear correlation as low as 0.7924 and nonlinear model correlation as high as 0.9370 when modeled with temperature. The β-gauge shows no relationship with season or meteorological variables. It exhibits a linear correlation as low as 0.8505 with the FRM and a nonlinear model correlation as high as 0.9339 when modeled with humidity. The nephelometer shows no relationship with season or temperature but a strong relationship with humidity is observed. A linear correlation as low as 0.3050 and a nonlinear model correlation as high as 0.9508 is observed when modeled with humidity. Nonlinear models have higher correlation than linear models applied to the same dataset. This correlation difference is not always substantial, which may introduce a tradeoff between simplicity of model and degree of statistical association. This project shows that continuous monitor technology produces valid PM_2.5 characterization, with at least partial accounting for variations in concentration from gravimetric reference monitors once appropriate nonlinear adjustments are applied. Although only one regression technically meets new EPA National Ambient Air Quality Standards (NAAQS) Federal Equivalent Method (FEM) correlation coefficient criteria, several others are extremely close, showing optimistic potential for use of this nonlinear adjustment model in garnering EPA NAAQS FEM approval for continuous PM_2.5 sampling methods.     

1987 Joint EPRI/EPA Symposium on Stationary Combustion NOX Control

From March 23rd to 26th, 1987, the city of New Orleans hosted 350 attendees, including representatives from 15 foreign countries, at the 1987 Joint Symposium on Stationary Combustion NO_x Control. Cosponsored by the Electric Power Research Institute (EPRI) and the U.S. Environmental Protection Agency (EPA), the symposium provided attendees the opportunity to hear 49 papers in nine sessions covering technological and regulatory developments on NO_x control in the United States and abroad since the May 1985 symposium in Boston. Session topics included general environmental issues, low-NO_x combustion equipment (i.e., low-NO_x burners, reburning, etc.), flue gas treatment, fundamental combustion research, and special issues for cyclone coal-fueled boilers, oil- and gas-fired boilers, and industrial combustion applications.

Advances to the state-of-the-art presented at this symposium include: improved and/or newly applied combustion modifications for pulverized coal-fired boilers; further analyses of reburning, the leading combustion modification option for cyclone-equipped boilers; initial experiences with catalytic flue gas treatment in Europe; studies of NO_x control retrofit options for oil- and gas-fired utility systems; and new technology developments for coal, oil, and gas fueled utility and industrial combustors.

This paper summarizes those presentations that discussed significant changes since May 1985 in areas of potential interest to EPRI and its utility members. Where appropriate, they include our perspectives on the applicability of these newly disclosed findings to utility systems.     

Acid Particles and the Tracheobronchial Region of the Respiratory System—An “Irritation-Signaling” Model for Possible Health Effects

This paper explores some detailed mechanistic hypotheses for the possible action of acid particles on the tracheobronchial region of the human respiratory system. Because of the buffering capacity and volume of mucus produced per day it appears doubtful that ordinary ambient exposures to acid particles could markedly change the overall pH of tracheobronchial mucus considered as a whole. However it is possible that individual acidic particles could contain enough acid to deliver localized “irritant signals” that could be the triggers for enhanced mucus secretion and cell division in sensitive portions of the bronchial tree, and thereby contribute to the processes involved in chronic bronchitis.

Depending on the exact pH depression required for a “signal” to be perceived by the tracheobronchial epithelium, the acid content of the incoming particles per unit weight, and the effect of neutralization by ammonia in the upper respiratory tract, the minimum size of an acidic particle required to deliver a perceptible signal might range from about 0.4 to 0.7 microns for portions of the epithelium that are frequently swept by 4-micron mucus droplets. (For unprotected epithelium, however, it is conceivable that the minimum effective size for acid particles could be less.) Since particle number per unit weight declines dramatically with increasing particle size, the most potent fraction of particles in terms of signals delivered per μg/m³is likely to be just above the minimum size that is needed to produce an effective signal. The model developed here makes predictions of the relative potency of particles of different size and acid delivery capacity that could be tested in both experimental animal systems and human epidemiological studies.     

An Evaluation of the Semi-VOST Method for Determining Emissions from Hazardous Waste Incinerators

The Semi-Volatile Organic Sampling Train method was investigated to determine its reliability and to determine the bias and precision of the method when used to determine emissions from hazardous waste incinerators. Experiments showed that the matrix and sampling variables usually involved in sampling emissions from a hazardous waste incinerator had no significant effect on the recovery of 11 different organic compounds. Significant losses of the sampled compounds can occur during sample preparation. The degree of loss appears to be directly related to the compounds, vapor pressure. These losses can be corrected for by adding deuterated surrogates to the sample and analyzing the surrogates along with the native compounds.

The bias determination was based on dynamic spiking of the sampling train with five deuterated organic compounds selected from Appendix VIII of the Resource Conservation and Recovery Act regulations. The results show biases of from -1 ± 8 percent to -18 ± 27 percent for chlorinated and nonchlorinated compounds. Pyridine, a water-soluble compound, showed a larger bias of-29 ± 13 percent. Particular attention to the recovery of water soluble compounds is necessary to minimize bias in their determinations. Further work is needed to determine the reliability of laboratory-determined retention volumes that are used to determine sampling conditions.