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Analytical procedures for the speciation of hydrocarbons and oxygenates (ethers, aldehydes, ketones and alcohols) in vehicle evaporative and tailpipe exhaust emissions have been improved for Phase II studies of the Auto/Oil Air Quality Improvement Research Program (AQIRP). One gas chromatograph (GC) was used for measurement of C1-C4 species and a second GC for C4-C12 species. Detection limits for this technique are 0.005 ppm C or 0.1 mg/mile exhaust emission level at a chromatographic signal-to-noise ratio of 3/1, a ten-fold improvement over the Phase I technique. The Phase I library was modified to include additional species for a total of 154 species. A 23-component gas standard was used to establish a calibration scale for automated computer identification of species. This method identifies 95±3% of the total hydrocarbon mass measured by GC for a typical exhaust sample. Solid adsorbent cartridges or impingers were used to collect aldehydes and ketones.

An analytical method for the determination of hydrocarbon and ether emissions from gasoline-, methanol-, and flexible-fueled vehicles is described. This method was used in Phase I of the Auto/Oil Air Quality Improvement Research Program to provide emissions data for various vehicles using individual reformulated gasolines and alternate fuels. These data would then be used for air modeling studies. Emission samples for tailpipe, evaporative, and running loss were collected in Tedlar bags. Gas chromatographic analysis of the emissions samples included 140 components (hydrocarbons, ethers, alcohols and aldehydes) between C1 and C12 in a single analysis of 54-minutes duration. Standardization, quality control procedures, and inter-laboratory comparisons developed and completed as part of this program are also described.

A gas chromatographic instrument has been developed to measure methane in diluted automotive exhaust. Measurements can be made on a 60-second cycle with a standard deviation of 0. 06 ppm methane and with no known interferences. In addition, a prototype selective combustor for continuous methane determination in exhaust has been evaluated and found to be satisfactory.

The barium ion titration method as used for determining the amount of sulfuric acid and soluble sulfate aerosol emitted by automobiles is described. Results obtained by this method are compared with those obtained by the barium chloranilate (BCA) method. It is concluded that the described titration method is a low-cost and convenient method for the analysis of automotive derived sulfates. Its precision is good, its sensitivity is adequate, and its accuracy is as good as the BCA method.