While the detrimental effects of inhaling secondhand tobacco smoke are well-documented, it can be difficult to determine just how much of that smoke people are exposed to. After all, we know that smokers inhale smoke from each of their cigarettes, but what percentage of that smoke reaches their family members or co-workers? Scientists at New Hampshire's Dartmouth College have created a portable sensor, in order to find out.

Currently in prototype form, the device is claimed to be "the first ever secondhand tobacco smoke sensor that records data in real time." It uses polymer films to measure ambient nicotine vapor molecules, along with a chip that records the data. Utilizing that technology, it not only measures the amount of smoke in its immediate environment (right down to the number of cigarettes smoked), but also keeps a record of when and where the exposure took place.

It can also detect and measure thirdhand smoke, in the form of nicotine that off-gasses from things like clothing and furniture upholstery.

In its current form, the sensor is slightly smaller and lighter than a smartphone. The scientists hope to develop it into a smaller wearable device that's both affordable and reusable. According to the college, existing secondhand smoke sensors are relatively inaccurate, expensive, and "provide only an average exposure in a limited area over several days or weeks."

Tests of the new sensor in a lab-based "smoking chamber" have reportedly gone well, with plans calling for clinical trials to follow soon. Ultimately, it is hoped that the device could be used to help enforce smoking bans in public places, and to show smokers how much of their smoke reaches people such as their children.

A paper on the sensor was recently published in the journal Nicotine and Tobacco Research.