When someone is really intoxicated, they may not be very cooperative when told to blow into a breathalyzer. There could soon be a more passive but just as accurate alternative, though, in the form of an earmuff that measures blood alcohol levels.
Breathalyzers work by measuring ethanol levels in a person's breath, which correspond to levels in their bloodstream. Ethanol is also released through the skin, although the concentrations are too low for an accurate reading on most parts of the body. Additionally, the presence of sweat glands in the skin may skew the readings.
Seeking a more reliable alternative, scientists from Tokyo Medical and Dental University instead looked to the ears. Not only is ear skin known to release more ethanol than skin on areas such as the hands or arms, but it also contains relatively few sweat glands. With these facts in mind, the researchers set about modifying an existing set of off-the-shelf protective earmuffs.
In the resulting experimental system, filtered air is pumped into one of the muffs via a hose that runs into a hole at the top. That air passes through the sealed chamber surrounding the ear, collecting emitted ethanol gas as it does so, and is then drawn out of the muff via a hose at the bottom.
That lower hose runs to a separate device known as a bio-sniffer. When "excited" by ultraviolet light, a sensor within that bio-sniffer fluoresces in the presence of ethanol gas – the greater the concentration of ethanol, the more intense the fluorescence.
In lab tests, the earmuff was placed on three male volunteers who had each consumed a set amount of alcohol. At regular intervals over the next 140 minutes, their blood alcohol levels were checked via both the earmuff and a conventional breathalyzer. The readings of the two devices were found to be consistently similar.
It is now hoped that once developed further, the technology could be utilized as an alternative to breathalyzers, and perhaps also as a means of detecting different skin-released gases associated with diseases.
A paper on the research, which was led by Prof. Kohji Mitsubayashi, has been published in the journal Scientific Reports.
Source: Scientific Reports via EurekAlert