This is Scientific American 60 Second Science.

I'm Cynthia Graber.

Got a minute.

Devices that detect potentially hazardous gases or airborne environmental pollutants are

out there,

but they're expensive and bulky.

Now, MIT researchers say they've developed a way to get the same detection abilities

with your smartphone.

The research team modified what are called

near field communication tags or

NFC tags. Smartphones with NFC capabilities send out magnetic field pulses.

The magnetic field creates an electric current on the tag that the phones pick up.

Such systems are typically used to track products or drugs.

For the new application, the scientists added links to the circuit made of carbon nanotubes.

Each link responds to one particular gas by changing how the nanotubes. Each link responds to one particular gas by changing how the nanotubes

conduct electricity. By sensing the change in electric current on the tag, the smartphone

signals that it has detected the gas in question. The method was tested with ammonia cyclohexanone and hydrogen

peroxide and the tags could sense the substances at levels of a few parts per million.

The research is in the proceedings of the National Academy of Sciences. Such inexpensive tiny

tags require no external power. The scientists say their NFC tag system has the

potential to be widely used to monitor gases that can affect health, safety, and the environment.

Thanks for the minute. For Scientific American 60 Second Science, I'm Cynthia Graber.

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