James L. Cheney

Profiles of Organic Particulate Emissions from Air Pollution Sources: Status and Needs for Receptor Source Apportionment Modeling

Trace elements are widely used to identify the sources of airborne pollutants and to apportion their contributions to the ambient aerosol through receptor models. Due to the impending loss of Pb and Br as automotive emissions tracers and our inability to distinguish among certain types of emissions using tracer elements, there is a need to identify alternative emissions tracers. Organic compounds may also be useful tracers for sources of particles or toxic air pollutants which do not emit trace metals. Published data on the organic composition of source emissions were reviewed to determine their usefulness for these purposes. Factors affecting the variability of reported organic emissions source profiles have been discussed in detail in this review. The existing data indicate that it may be possible to use polycyclic aromatic hydrocarbons, alkanes and certain apparently unique organic compounds to assist in distinguishing among emissions from certain particulate pollutant sources. These compounds can prob...

The Detection of Sulfur Dioxide Utilizing a Piezo-Electric Crystal Coated with Ethylenedinitrilotetraethanol

Abstract A considerable number of compounds have been shown to be sensitive to sulfur dioxide sorption using quartz crystals. To utilize the technique for the continuous measurement of SO2, coating loss has been shown to be a major limitation. For such a continuously flowing system a previous coating, triethanolamine, was found to evaporate at undesirable rates when used at high enough temperatures and flow rates for an adequate response time. Methods of remedying this problem have led to a new SO2 sensitive coating, ethylenedinitrilotetraethanol. This work presents the technique of coating application, the sensitivity relative to the amount of coating applied, a comparison of totally coated crystals to center coated ones, and a comparison of the new coating relative to the previously used triethanolamine.

Design and Performance of a Laboratory Sulfuric Acid Generator

A laboratory sulfuric acid (H/sub 2/SO/sub 4/) generator was designed and constructed to simulate sulfur gas levels in combustion gases. The acid generator produces SO/sub 3/ by the catalytic (platinum-black) oxidation of SO/sub 2/. By controlling the catalyst temperature (20/sup 0/C-538/sup 0/C), a desired SO/sub 3//SO/sub 2/ concentration ratio (30% to 100% conversion of SO/sub 2/ to H/sub 2/SO/sub 4/) can be attained. A separate control system holds moisture at desired levels in the output gas stream. The generator was developed to produce (at output volumes of 1-20 L/min and output temperatures up to 290/sup 0/C) a sustained moisture, SO/sub 2/ and H/sub 2/SO/sub 4/ gas stream, which could serve both as a method development and monitor performance evaluaton tool. The results of an evaluation of the H/sub 2/SO/sub 4/ generator showed that regulated gas stream moisture levels (10.8%-11.3% v/v) were held constant over an extended period of time (168 h). A constant rate of acid could be generated by varying either the SO/sub 2/ dilution or the converter temperature. A purge technique developed during the study decreased the stabilization time required (from 3 h to 30 min) following a converter temperature change.

Improvements in the methodology for measuring hydrochloric acid in combustion source emissions

Abstract In sampling gaseous hydrochloric acid in combustion source emissions by the standard method (collection of particles in a probe plug followed by absorption of gaseous HCl in an impinger solution), there is a potential for error due to interaction of HCl with the filtering medium and/or with particles on the filter. A laboratory study was conducted to examine the interaction of gaseous HCl with glass and quartz media and with particles from coal‐fired and incinerator boilers. Also, some source sampling results obtained by different methods at cement production plants, oil‐fired boilers, and a coal‐fired boiler were examined. On the basis of both studies, it is recommended that sampling for gaseous HCl in combustion source emissions employ a quartz filter medium, high‐velocity sample flow, minimum filter temperature, and minimum sample volume. This approach is expected to yield the most accurate HCl mass emission rates for source categories having significant chlorine in fuels or processes.

Effects of Gaseous Hydrochloric Acid on Source Particulate Characterization

Abstract Particulate characterization filters acquired at a Portland Cement Plant were analyzed by x-ray fluorescence spectroscopy. A wide variation in the Cl− levels on the various types of filter media suggested the collection of gaseous HCl by some media. The results from a subsequent laboratory study of the reaction of gaseous HCl with the various filter media indicated a significant reaction between HCl and some of the media. Thus, particulate Cl− measurements must be interpreted with caution.

The Detection of Source Levels of Sulfur Dioxide Using a Piezo-Electric Detector and Permeation Membrane

Abstract The detection of gaseous pollutants using a coated vibrating quartz crystal has been the topic of several studies. Detection of sulfur dioxide with an alkanoamine-coated crystal has already been shown feasible for ambient air pollution levels. Detection of sulfur dioxide at source levels using the piezo-electric method has previously not been proven successful. This work presents the refinements, calibration, and performance of a source monitoring instrument which incorporates a sulfur dioxide permeable membrane as a dilution interface.

The use of isopropanol to distinguish H2SO4 from particulate sulfate on filters

Abstract Potential interferences in the anhydrous isopropanol (a‐IPA) extraction method for separating sulfuric acid from particulate sulfate on filters were investigated. The method involves separation and recovery of the acid with a‐IPA, followed by aqueous extraction of the particulate sulfate. Analysis for sulfate in the two separate fractions was performed by ion chromatography. The solubility of ammonium sulfate in a‐IPA was measured and the effects of temperature and moisture content of the solvent on ammonium sulfate solubility were determined. The solvent recovery procedure was used to analyze samples collected at an oil‐fired utility boiler. Before analysis, each filter was cut in half and one half of each filter was exposed to an ammonia atmosphere to neutralize any free sulfuric acid. All filter halves were then extracted with a‐IPA followed by a separate aqueous extraction by ultrasonication. Neither a small uptake of moisture by the a‐IPA nor elevated temperatures up to 30° C had a significa...

Measurements of Primary Sulfates with an Acid Condensation System

Two techniques were used to measure primary sulfuric acid and sulfate emissions from two small package boilers burning nominal 0.3% sulfur fuels, one with 11 ppM vanadium and one with 4.3 ppM vanadium. Several of the particulate fractions from both sampling methods were analyzed for sulfuric acid using a selective solvent determination (SSD) procedure. The sulfuric acid present on the filters accounted for a minimum of 11% of the particulate emission rates. The observed conversion of sulfur dioxide to primary sulfate or primary sulfuric acid is reduced considerably when sulfate ion detected in an isopropanol impinger is attributed to sulfur dioxide conversion in the solution rather than to primary sulfuric acid. An additional reduction occurs when the method of calculating the conversion is based solely of sulfur weight. This study gives a fourfold reduction in percent conversion when compared to a similar study conducted earlier. Suggestions are offered for improvements in measurement methods and for a consistent technique for calculating sulfur conversion.

Measurements and estimations of local impacts from fugitive emissions

Abstract A laboratory and field sampling program was conducted to study the ground‐level concentrations of benzene due to fugitive emissions. The three‐day field sampling study addressed benzene sampling in the downwind plume line at ground level within the first 500 meters of a maleic anhydride plant. The laboratory evaluation of the benzene measurement technique used, along with the results of the ground‐level sampling are presented. Statistical analyses of the measurement data indicated the best fit formula to the actual data was the y = Kin x. From a statistically determined source strength factor, the point source and finite line source models were plotted and compared to the actual data. It was found that within 200 meters, ground‐level concentrations of benzene could be attributed to fugitive emissions while at a distance both the fugitive and the stack emissions contributed to the measured concentrations.

Applications of Aldehyde Detection Methods for Source Emissions Measurements

Abstract Aldehyde emissions from two types of sources were measured by three measurement method approaches. The two sources were a municipal incinerator and a phenolic resin manufacturing process. The three measurement methods were: collection of the aldehydes in a basic peroxide solution with subsequent detection by Ion Chromatography, collection of the aldehydes in a bisulfite solution with subsequent determination of total carbonyl with a titrimetric procedure, and collection of the aldehydes in a dinitrophenylhydrazine solution followed by detection of the respective derivatives by high performance liquid chromatography. The results indicate several limitations to the peroxide approach and potential collection efficiency problems with the derivative method. The need to develop further measurement methodology for such sampling and detection exists.