“The air may seem clear at Bodega Head, 40 miles up the coast from San Francisco — but thousands of particles smaller than red blood cells drift in each cubic foot. Some have traveled a single mile; others, thousands. Prather’s machine sniffs them one by one, with a precision that no human nose can match. Its laser vaporizes five or six per second, spattering their guts across an ion detector, producing the chemical barcodes she peruses. A digital tally twirls alongside, like an odometer, too quickly to read — over 4,600 particles vaporized so far this morning”.
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