Cell Phone Air Sensors

Cell Phone Air Sensors Photo Credit: Clipart.com

Installing chemical sensors in cell phones could create a worldwide system for identifying dangerous airborne toxins.


Cell phones as first responders. I'm Bob Hirshon and this is Science Update.

The Department of Homeland Security wants to put chemical sensors in cell phones—so they can detect toxins in the air, and relay the location to authorities. The
University of California at San Diego is developing one sensor in collaboration with a company called Rhevision. According to biochemist Michael Sailor, different areas on the thumbnail-sized chip can be engineered to detect different chemicals.

Either chemicals that might be coming out of an industrial accident, a Homeland Security kind of event—terrorist event, for example—or even something as simple as carbon monoxide in a conventional fire.

They'll start by putting the chips in first responders' cell phones. If that works, the sensor could someday become a standard phone feature, like a Web browser or a camera. I'm Bob Hirshon, for AAAS, the science society.

Making Sense of the Research

Cell phones have dramatically changed modern life, especially with the addition of cameras, Web browsers, GPS, and other features. But even more than their increasingly sophisticated capabilities, the fundamental cultural power of cell phones comes from the fact that so many people have them. If they were simply a novelty, confined to a small circle of technology lovers, our world would be a lot different (and barely imaginable for people under 25).

In effect, a large percentage of the population now carries around a little computer all day long—a computer that's always on, with the ability to communicate and fix its exact location on the globe. Not long ago, if someone had proposed setting this up deliberately, for scientific purposes, it would have seemed ridiculous. And yet, the world just happens to have turned out that way. 

The Department of Homeland Security hopes to take advantage of this situation by putting chemical sensors in cell phones. Imagine, for example, if a dangerous chemical were leaking from a factory. Using traditional methods, it might take quite a long time to notice the leak. However, if cell phones had the capability to detect the chemical, a few people passing nearby would be all it took to set off an alarm. The cell phones would detect traces of the chemical in the air, and relay the information to some kind of central command system, along with the exact location of the cell phone at the time of detection. Authorities could be dispatched to the scene right away—all within seconds, with no need for the cell-phone owners to even notice what was happening. (Of course, if the chemical were highly toxic, an alarm on the cell phone itself would be nice.)

The sensor that Rhevision and the University of California at San Diego have worked on responds to different chemicals by changing color. It's possible to pack a single chip with many different tiny pores, each of which respond to a different chemical. The human eye may not be able to see the tiny changes, but a standard cell-phone camera can resolve a picture finely enough to detect them. So their system relies on a digital camera to watch the chip for color changes.

For starters, they'll put the chips in the cell phones of first responders, like paramedics and firefighters. They're the best people to test the device on, in part because they're most likely to be exposed to dangerous airborne chemicals. But in an ideal scenario, every new cell phone would come with one of these chips in it, creating a worldwide chemical detection system that never could have been built from scratch.

Now try and answer these questions:

  1. Why does the Department of Homeland Security want to put chemical sensors in cell phones?
  2. What's the advantage of doing this, as opposed to installing sensors in public places?
  3. Suppose a cloud of toxic chemicals was drifting across a city. How might the cell-phone network help authorities track it?
  4. Can you think of other ways that cell phones might be used for public benefit?

You may want to check out the June 4, 2010 Science Update Podcast to hear further information about this Science Update and the other programs for that week. This podcast's topics include: ecologically-friendly plastic, a cleaner way to produce hydrogen fuel, cell phone air sensors, the perils of spaceflight, the ethical implications of synthetic life, and more.

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