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Lawsuits, court fines, and insurance claims can be generated by the odours as well as the noise, vibrations and dust, which are produced daily by industrial processes.

The only place the words odour, sound, and vibration appear in the Ontario Environmental Protection Act is under the definition of "contaminant", as "any solid, liquid, gas, odour, heat, sound, vibration, radiation, or combination of any of them resulting directly or indirectly from human activities that may cause an adverse effect." Because there is no parameter or number limit associated with these words, it means that an odour, for example, becomes a contaminant when a neighbour complains about it.

Plumes today are not those shown in photographs of smoke stacks from the last century belching black smoke. Today it is rare to see a plume other than white water vapour. Plumes contain colourless gases and move in the direction of the prevailing wind. They diffuse, that is spread out, both horizontally and vertically. Since they are heavier than air, they tend to sink as they cool. As a result, depending on wind conditions, they come back down to ground level, creating a "Point of Impingement" (POI). Wind speed determines how far away the POI occurs on a particular day and, of course, direction controls which homes or buildings are affected.

Odour plumes, in fact, are quite common. Restaurants and coffee shops seem to depend on attracting customers with the odour that wafts out of their premises. However, the odours that neighbours complain about are the ones that are carried in the plume coming from an exhaust stack on a plant as much as a mile away. Occasionally chicken hatcheries, duck farms, pigeries, and stock yards have been identified as sources of odour and in some cases the neighbours have exerted enough pressure to persuade the owner to move operations elsewhere.

Today, using gas chromatographs equipped with mass spectrometers and sensitive sampling equipment, it is possible to identify odours and to trace them back to particular source stacks.

Once the manufacturer identifies which stack or stacks are the main odour producers, there are a number of treatments available such as carbon absorption, catalytic destruction or thermal destruction (high temperature) or a combination of methods to consider. This way, one of more modifications can produce a significant reduction in the odour detected in the neighbours backyard or on their balcony. It is much more cost effective to treat an individual stack, even a large one, than to try to enclose a large facility in some sort of cocoon and to treat all the air which leaves the building.

In Ontario, many industrial operations, once stand alone, are now surrounded by homes. Some of these operations paint their products. Paints which use organic solvents (VOC) are the mainstay of automotive painting plants. This applies whether they are corner garages, body shops doing fairly simple repairs, or whether they are parts producers with hundreds of parts per shift coming out of their ovens. Unfortunately, some solvents have readily detectable odours.

For major paint users, probably the lowest cost solution is simply to ask their paint supplier to change the solvent system of the paint in order to reduce or eliminate a particularly odorous solvent component. Solvents vary considerable in their odour detection threshold (ODT) and this has been a straightforward solution where the neighbours are not too close to the facility.

Walters Forensic has been asked to measure air emissions and to advise on the remediation and control of industrial odours.

The information contained in this web site is intended for marketing purposes only. It is not all-inclusive, and does not fully describe the many and varied services that the company provides, nor does it completely describe the education, training, skills, or expertise of our staff.


Walters Forensic Engineering | 277 Wellington Street West, Suite 800 | Toronto, ON M5V 3H2
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