SAN FRANCISCO (KCBS)— An estimated $30 billion in U.S. currency is illegally smuggled into Mexico each year from the United States, but research is being done to help U.S. border-patrol agents detect the so-called dirty money.

Researchers at the 248th National Meeting and Exposition of the American Chemical Society, happening in San Francisco, presented evidence on Tuesday that a portable device can identify specific vapors given off by U.S. paper money.

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Dr. Joseph Stetter, an East Bay-based chemist who is a member of the research team and is also the president of KWJ Engineering, says the device works more on a matter of amount and size rather than a $20 bill giving off a different odor than a bill of a much higher denomination.

“It’s kind of like a doctor when they detect an infection. We have lots of bacteria on us, but when it becomes overwhelming, and then of course it becomes an infection. It’s the same thing with chemicals, vapors and odors,” he said.

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Every material has its own particular odor according to Stetter. “The best example is dogs and bears who can find prey from great distances.”

The device will use a “smart” algorithm to figure out one substance from another.

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As far as when the device could be ready for use at the border, Stetter estimates it will be a couple of years before the technology will be replacing dogs.