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Reading The Air

September 17, 2009
by Nathanael Johnson

Biochemistry professor Allen Goldstein hadn’t intended to investigate the drug trade, he was just trying to build a machine that would let him measure air pollution. The instrument he’d been designing was one that could pluck compounds out of the air and analyze them on the fly. Other machines already existed that could suck in pollutants and tell scientists what they were, but generally, scientists studying air pollution (or the atmosphere) would draw air through a filter all day, then send that filter off to a lab for analysis, making the process slow and expensive.

This new machine had its analysis built-in. Every hour Goldstein and his team received a reading, showing which compounds were in the air. They could identify traffic rush hours by watching for elevated levels of signature compounds in gas and diesel exhaust. In the mornings, as coffee shops did their roasting, caffeine compounds spiked. These were things they’d expected, but then they noticed truly surprising compounds: marijuana, cocaine, and methamphetamines. “It was certainly unexpected,” Goldstein says. “I think we were all a little excited to see that.” Excited, because finding traces of hidden drug use was an indication that the machine would live up to its purpose—allowing scientists to read information in the air quickly, while the compounds were still there.

In its finished state the device looks a bit like a copy machine, but Goldstein’s team is already working on the next generation, which currently has a much less tidy appearance. Postdoctoral research scientist Dave Worton has the guts of the newest rendition spread out like an erector set in a Hilgard Hall lab room. A fan brings air through a series of tubes and sensors secured in place by tinfoil. Worton goes over the pieces millimeter by millimeter, checking for leaks and blockages.

Instead of using this machine to bust potheads, scientists will employ it to monitor pollutants more closely than they could in the past. With an older, 24-hour machine it was impossible to tell, for instance, whether pesticides were dangerously high and only in the air for 1 hour or acceptably low and in the air for 24 hours. Because this instrument takes measurements every hour, it will show the difference. And because the machine also provides a high volume of specific data, scientists can actually trace compounds back to their source—Goldstein took the device to Nova Scotia and was able to identify particles blowing in from forest fires in Alaska.

As for the drug readings, Goldstein says, “Sure, I guess it’s interesting.” But he believes this instrument will provide far more important revelations by helping us understand the mechanics of global warming and the sources of pollution. Nonetheless, as these types of machines become more common, they are going to reveal a previously hidden dimension to our world, contributing both to science and to neighborhood gossip.

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