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EMISSIONS FROM TWO OUTBOARD ENGINES OPERATING ON REFORMULATED GASOLINE CONTAINING MTBE
Citation:
Gabele, P A. AND S M. Pyle. EMISSIONS FROM TWO OUTBOARD ENGINES OPERATING ON REFORMULATED GASOLINE CONTAINING MTBE. ENVIRONMENTAL SCIENCE & TECHNOLOGY 34(3):368-372, (2000).
Description:
Air and water pollutant emissions were measured from two 9.9 HP outboard engines: a two-stroke Evinrude and its four-stroke Honda counterpart. In addition to the measurement of regulated air pollutants, speciated organic pollutants and particulate matter emissions were determined. Aqueous samples were analyzed for MTBE (methyl tert-butyl ether) and BTEX (benzene, toluene, ethyl-benzene, and xylene) emission rates. Compared to the four-stroke engine, the two-stroke had dramatically higher levels of toxic organic and particulate matter emissions. The organic material emitted from the two-stroke engine resembles the test gasoline due to the predominance of unburned fuel. Emission rates for PM10 (particulate matter with a diameter of 10 mm or less) are equal to those for PM2.5 , implying that emitted particles are all in the respirable range. Aqueous emissions from the two-stroke are also higher: the two-stroke's BTEX and MTBE emissions are, on average, 5 and 24 times higher, respectively, and 3-10 percent of the MTBE fed to the engine is emitted to the water. Aqueous emission rates, expressed in brake-specific units, tend to increase with decreasing engine load, as do the atmospheric emission rates.
The information in this paper has been funded by the Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.