3000 odour complaints tested by nose

07:23, Feb 01 2014
Nose test
SNIFF TEST: Environment Canterbury officers establish resource consent violations using international standards and calibrated noses.

In the ongoing fight against olfactory crimes, specially calibrated Christchurch noses are sniffing out the objectionable, the offensive and the downright stinky.

These noses have been subjected to a complex globally recognised test and measured against the best noses worldwide to ensure the most accurate sniff.

Environment Canterbury's 21 Resource Management Act (RMA) officers all have their noses calibrated, via the Olfactometry Test.

Environment Canterbury sniff test
SNIFF TEST: Environment Canterbury officers establish resource consent violations using international standards and calibrated noses.

Calibration plays a major role when a breach of a resource consent is in question.

The emotions of a complainant and the smell are closely connected, but officers must set emotion aside and remain impartial. It is impossible to measure smell accurately and the enforcement of odour-related consent violations is a challenging field.

ECan RMA monitoring and compliance manager Brett Aldridge says his team looks at facts.


ECan receives about 5000 complaints a year, about 60 per cent of which are odour-related, Aldridge says.

Those facts must stack up in a court room and meet the "beyond reasonable doubt" standard.

To assist officers in meeting such high standards, ECan follows its own specific guidelines, Ministry for the Environment standards and international best practice.

The first step is to calibrate the nose. Some people are more sensitive than others. To ensure fairness when assessing an odour, officers must know where they stand on the sensitivity scale.

Fortunately, the Olfactometry Test is used worldwide and every participant's results recorded.

Put simply, sensitivity to smell is tested with a specific complex chemical compound. It takes the best part of a morning, and requires officers to sniff the compound sprayed in a dark booth at various intensities.

By checking an individual's responses to odour against thousands of results around the world, relative sensitivity can be measured.

An officer acknowledges their own sensitivity in the assessment allowing for impartial results to be recorded.

Smell is complex. Every smell, Aldridge says, has character, hedonic tone, and a profile. Officers use an internationally recognised assessment technique called FIDOL - frequency, intensity, duration, offensiveness and location.

Odour Complaint Investigation form in hand, an officer does a 360-degree sweep of the area in question, sniffing every 10 seconds and noting down all the above smell indicators, plus wind direction, temperature and cloud cover.

All things considered, the officer decides whether the smell in question is offensive or objectionable.

"It takes a huge amount of experience and knowledge to get to that point," Aldridge says.

It doesn't have to be ongoing to be offensive, nor does it need to be offensive in small doses. Some smells are reasonably inoffensive for short periods of time, but over hours or days, may become unbearable.

Testing systems and calibrated noses aside, Aldridge says smell remains highly subjective.

"If someone could figure out an absolutely scientific way to measure smell, they'd make a fortune."

The Press