Intelligent Systems Report € October € 1996 € Volume 13€ No. 10

Electronic noses sniff out toxic waste

The Pacific Northwest National Laboratory (Richland, Wash.) is exploring the technologies required to perform environmental restoration and waste management in a cost-effective manner. This effort includes the development of portable, inexpensive systems capable of real-time identification of contaminants in the field. As part of this effort, neural networks are being combined with chemical sensor arrays and spectrometers for use in prototype electronic "artificial noses."

During operation, a chemical vapor or odor is blown over the sensor array, the sensor signals are digitized and fed into the computer, and the neural network (implemented in the software) then identifies the chemical. The benefits of electronic noses include compactness, portability, real-time analysis and automation.

Environmental applications of electronic noses include: identification of toxic wastes; analysis of fuel mixtures; detection of oil leaks; identification of household odors; monitoring air quality; monitoring factory emission; and testing ground water for odors.

Because the sense of smell is an important sense to a physician, electronic noses also have applicability as a diagnostic tool. An electronic nose can examine odors from the body (e.g., breath, wounds, body fluids, etc.), and identify possible problems. Currently, an electronic nose for examining wound infections is being tested at South Manchester University Hospital.

While the inclusion of visual, aural and tactile senses into telepresence systems is widespread, the sense of smell has been largely ignored. Recently, Pacific Northwest National Lab proposed an application of electronic noses for telesurgery. The electronic nose would identify odors in a remote surgical environment; these identified odors would then be electronically transmitted to another site where an odor generation system would recreate them.

Currently, the biggest market for electronic noses is the food industry. In some instances they can be used to augment or replace panels of human experts. In other cases, they can be used to reduce the amount of analytical chemistry that is performed in food production, especially when qualitative results will do. Existing applications include: inspection of food by odor; grading quality of food by odor; fish inspection; fermentation control; automated flavor control; monitoring cheese ripening; beverage container inspection; microwave oven cooking control; and grading whiskey.

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