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Sniffing out a stench
TECHNOLOGY
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Fieldnotes West Side industrial district, Chicago fivesenses
to the edge of detection. The idea is to find out the level you can no longer detect the smell, which is measured in the number of dilutions needed to get there. We stand across the street from an oil terminal that smells strongly of rot, probably due to a sulphur compound used during
“Some states in the US regulate smell, with hefty fines for companies that emit strong odours” oil processing. Smith buries her nose in the nasal mask and inhales, drawing a little harder than normal. The oil terminal registers as a level-30 dilution. Those states in the US that regulate odour allow a dilution level of 7. Any smell –Picking up a stink– measuring higher is considered a “nuisance” and can lead to hefty fines. The Nasal Ranger measures smells up to 60 dilutions – enough to send you reeling if sampled undiluted – and by fitting it with a spare dial it can measure odours Chemical plants, landfills, oil refineries… foul odours are detectable at 500 dilutions. everywhere. Now we can keep them in check Some companies use the device to collect smell information in front is a black dial pierced by a pre-emptive strike before the The Nasal Ranger allows Smith Christopher Weber six holes ranging in size from the to precisely mix two streams of air introduction of regulations, says WITH its two waste water width of a pencil lead to a mere the Nasal Ranger’s inventor, before they hit her nose. Pungent treatment plants, a chemical pinprick. At the rear is a mask Charles McGinley of St. Croix ambient air enters through the company and a garbage truck that you place over your nose. The holes at the front and mingles Sensory, based in Lake Elmo, depot, Chicago’s West Side two are connected by a barrel of Minnesota. “They believe that with odour-free air that enters industrial district is one of the Teflon, which resists residual they do not smell that much and via the filters. Twisting the dial worst smelling places in the city. odours. Two carbon-based filters want to collect data to show that.” changes the ratio of foul to But foul odours are exactly why are mounted on either side. “In the past, to understand filtered air, diluting the stench I am here; I have come to witness the impact of an environmental the Nasal Ranger – the instrument odour, you would capture the of choice for measuring bad odour in a container, bring it smells – in action. to the laboratory, dilute it Electronic noses, which unlike when encountering them for the first My guide is Lynn Smith of successively, present those the Nasal Ranger don’t rely on the time. This accuracy persisted when Professional Service Industries, dilutions to panellists, and have human nose to detect an odour (see comparing the e-nose to the opinion an environmental consultancy them tell at what point they could main story), are also able to tell a foul of people from Israel and Ethiopia, firm based in Oakbrook Terrace, detect the odour,” says Pamela smell from a pleasant scent. suggesting that it is chemical Illinois. She relies on the Nasal Dalton of the Monell Chemical A team led by Rafi Haddad at the structure and biological hard-wiring, Ranger to find out whether smells Senses Center in Philadelphia, Weizmann Institute of Science in not cultural preference, which sets are potent enough to trigger who uses the Nasal Ranger to Rehovot, Israel, found that an e-nose the molecules people find offensive huge fines. monitor the smells emitted by correctly classified bad odours (PLoS Computational Biology, DOI: Smith’s trusty Nasal Ranger hog farms. “The Nasal Ranger 90 per cent of the time – even 10.1371/journal.pcbi.1000740). looks a bit like a handheld ray gun, allows you to do that in real time with a twist (see photo). On the in the field.” n
Sniffing out a stench
A nose for what’s nice
12 February 2011 | NewScientist | 21
For daily technology stories, visit www.NewScientist.com/technology
Fieldnotes West Side industrial district, Chicago fivesenses
to the edge of detection. The idea is to find out the level you can no longer detect the smell, which is measured in the number of dilutions needed to get there. We stand across the street from an oil terminal that smells strongly of rot, probably due to a sulphur compound used during
“Some states in the US regulate smell, with hefty fines for companies that emit strong odours” oil processing. Smith buries her nose in the nasal mask and inhales, drawing a little harder than normal. The oil terminal registers as a level-30 dilution. Those states in the US that regulate odour allow a dilution level of 7. Any smell –Picking up a stink– measuring higher is considered a “nuisance” and can lead to hefty fines. The Nasal Ranger measures smells up to 60 dilutions – enough to send you reeling if sampled undiluted – and by fitting it with a spare dial it can measure odours Chemical plants, landfills, oil refineries… foul odours are detectable at 500 dilutions. everywhere. Now we can keep them in check Some companies use the device to collect smell information in front is a black dial pierced by a pre-emptive strike before the The Nasal Ranger allows Smith Christopher Weber six holes ranging in size from the to precisely mix two streams of air introduction of regulations, says WITH its two waste water width of a pencil lead to a mere the Nasal Ranger’s inventor, before they hit her nose. Pungent treatment plants, a chemical pinprick. At the rear is a mask Charles McGinley of St. Croix ambient air enters through the company and a garbage truck that you place over your nose. The holes at the front and mingles Sensory, based in Lake Elmo, depot, Chicago’s West Side two are connected by a barrel of Minnesota. “They believe that with odour-free air that enters industrial district is one of the Teflon, which resists residual they do not smell that much and via the filters. Twisting the dial worst smelling places in the city. odours. Two carbon-based filters want to collect data to show that.” changes the ratio of foul to But foul odours are exactly why are mounted on either side. “In the past, to understand filtered air, diluting the stench I am here; I have come to witness the impact of an environmental the Nasal Ranger – the instrument odour, you would capture the of choice for measuring bad odour in a container, bring it smells – in action. to the laboratory, dilute it Electronic noses, which unlike when encountering them for the first My guide is Lynn Smith of successively, present those the Nasal Ranger don’t rely on the time. This accuracy persisted when Professional Service Industries, dilutions to panellists, and have human nose to detect an odour (see comparing the e-nose to the opinion an environmental consultancy them tell at what point they could main story), are also able to tell a foul of people from Israel and Ethiopia, firm based in Oakbrook Terrace, detect the odour,” says Pamela smell from a pleasant scent. suggesting that it is chemical Illinois. She relies on the Nasal Dalton of the Monell Chemical A team led by Rafi Haddad at the structure and biological hard-wiring, Ranger to find out whether smells Senses Center in Philadelphia, Weizmann Institute of Science in not cultural preference, which sets are potent enough to trigger who uses the Nasal Ranger to Rehovot, Israel, found that an e-nose the molecules people find offensive huge fines. monitor the smells emitted by correctly classified bad odours (PLoS Computational Biology, DOI: Smith’s trusty Nasal Ranger hog farms. “The Nasal Ranger 90 per cent of the time – even 10.1371/journal.pcbi.1000740). looks a bit like a handheld ray gun, allows you to do that in real time with a twist (see photo). On the in the field.” n
Sniffing out a stench
A nose for what’s nice
12 February 2011 | NewScientist | 21