A method has been developed to permit the simultaneous sampling of S02 and N02 from ambient air. Sulfur dioxide and N02 are collected on triethanolamine-impregnated glass fiber filters. After sampling, the filters are extracted, and the extract Is analyzed for sulfate, nitrite, and nitrate using Ion chromatography. Ambient concentrations are computed from the recovered nitrogen and sulfur and the sampled air volume. Laboratory tests were conducted to evaluate the performance of the method under various species concentrations and loadings, sampling rates, humidities, temperatures, flushing conditions, and Interferences. Results of these tests are described. Field measurements using the developed method compared favorably with other established methods. On the basis of the precision of field blanks, S02 and N02 detection limits of 0.3 and 0.2 ppb for 24-h samples and 0.04 and 0.03 ppb for 7-day samples were estimated. Precision estimates of better than ±15% were found, and accuracy within ±10% was observed.
A current EPA regulation prohibits the sale for burning in nonindustrial boilers of used oils and oil fuels contaminated above specified levels with total chlorine. Analytical techniques for determining total chlorine were evaluated to provide regulatory agencies and the regulated community with appropriate chlorine test methods. The techniques evaluated included oxygen bomb combustion followed by chemical titrations or ion chromatography, instrumental microcoulometry, field test kits, an instrumental furnace/specific ion electrode determinator, a device based on the Beilstein reaction, and x-ray fluorescence spectrometry. These techniques were subjected to interlaboratory testing to estimate their precision, accuracy, and sensitivity. Virgin and used crankcase oils, hydraulic and metalworking oils, oil fuels and oil fuel blends with used oils were tested. The bomb techniques, one of the test kits, microcoulometry and all but one x-ray analyzer were found to be suitable for this application. The chlorine furnace and the Beilstein device were found to be inapplicable at the levels of interest. The second test kit is being modified at this time.
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