There is now a scientific way to find out if someone is smoking, even if no one else is in the room. The nondescript white plastic box, brand-named FreshAir Sensor, gets installed into a wall outlet. Inside, a computer chip is coated with polymers that are sensitive to certain chemicals found in tobacco and marijuana.

Dartmouth chemistry professor Joseph BelBruno says he originally designed the detector for a public health worker who wanted to show parents that smoking in the house, even if not right in front of the kids, could still be harmful.

"That was the idea. It was meant not so much as a deterrent, but rather as an aid in trying to get parents to see that it was still affecting the health of their children," BelBruno recalled.

Over years of development, though, and with input from Dartmouth's Tuck School of Business, the marketing team is now targeting different users — primarily hotel owners who are tired of cleaning up after smokers in rooms designated as smoke-free. BelBruno doesn't worry about invading privacy in a situation like that.

"We thought about it but when someone rents a hotel room for the night and you sign that rental agreement at the beginning, you sign that you will not smoke in the room. So it's not as though we're misleading anyone by including the sensor in the room. What we are really doing is helping the hotel enforce what they want to enforce in the first place and what you sign when you sign into the hotel room," BelBruno said.

The detector can sense both tobacco and marijuana smoke, though it doesn't distinguish between them. So it's not likely to be used to alert, say, drug enforcers. But whatever you try to smoke in secret, this little white box may tell on you.

"That's one way to put it," BelBruno laughs. "Yes it can, and the idea is that when it detects a smoking event it will send a signal out over WiFi to let people know that smoking has happened. It will also record the signal so you could always go back later and retrieve it."

Two organizations, the Dartmouth Regional Technology Center and the Dartmouth Entrepreneurial Network, are helping to bring the new technology to market. The price has yet to be set, and a patent is still pending, but BelBruno says it could be available as early as mid-winter.