Odour is the property of a substance that activates the sense of smell and can cause nuisance and health damage. Companies can emit odour (emissions) to the environment that can bother people and lead to complaints and bad publicity. Fugitive emissions contribute to air pollution and climate change as well as an economic cost to the emitting company due to lost products.
The odour spreads through the air and causes an odour load to the living environment (emission). By odour load we mean the amount of odour, expressed in odour units per cubic metre of air, that ends up on an odour-sensitive object such as people’s homes. This amount can be measured or calculated.
Odour nuisance is the cumulated result of a repeated exposure to odour in the living environment. For that reason, odour also can entail health risks. Odour nuisance can lead to physical complaints such as headache, nausea, disturbed breathing and disturbed heartbeat. Odour can also cause psychological symptoms. For example, tensions, structural dissatisfaction with the living and living environment and reduction of activities outside the home.
Odour threshold value is the lowest concentration of a compound which gives an odour perception.
How do you rate odour?
The odour nuisance experienced by humans depends on a variety of factors, which may be dust, time of exposure, location and personal sensitivity. The duration and the frequency of exposure, the concentration and hedonic value (pleasantness or unpleasantness of an odour) are the most important of these.
An objective measure is required to test odour. This objective measure is expressed in European odour units per cubic meter of air (ouE/m³). When measuring odour with an olfactometer, a panel of people is exposed to the odour sample via the air dilution unit of the olfactometer. Initially, the odour is highly diluted so that the whole panel indicates that they cannot smell it. The operator then increases the concentration by reducing the pure dilution of the air a little and the members of the panel respond. The operator keeps increasing the odour by reducing the dilution air until half of the panel indicate that they can smell the odour, but the other half still cannot.
One odour unit per cubic meter is, by definition, the point at which 50% of the panel cannot smell the odour but 50% can. This dilution point is also called the perception threshold. The operator adds up all the dilutions that were required to reach that threshold to calculate how many odour units the original sample had once the perception threshold has been reached. If the sample was diluted 414 times, in order to reach 1 odour unit, then the sample odour concentration was 414 odour units (ouE/m ³) initially. This method is referred to as dilution-to-threshold, or D/T method.
Odour nuisance is mostly expressed as odour nuisance in the percentage of the population (% nuisance). This is the percentage of the population that sometimes or often suffers from that odour. A dose-effect relationship between odour load and the percentage of odour nuisance gives more insight into odour nuisance. But there is no single dose-effect relationship that applies to all odours and situations. The odour nuisance experienced depends, for example, on things like:
- duration of exposure
- exposure frequency
- nature and (un) pleasantness of the odour
The relation to the odour source naturally also has an influence on the odour experience. Examples of the relation to the odour source are:
- Is the odour source your employer or not?
- Have there been incidents that have threatened the safety of your living environment?
What is the odour potential of compounds?
The chemical nature of an odour compound can indicate the odour potential of a molecule. Table 1 gives an overview the odour potential of certain compounds.
Table 1: Overview of the odour potential of compounds
|High odour potentials
||Moderate odour potentials
|Low odour potentials
The odour control market
Several industrial activities can produce odour emissions that needs to be treated at the emission point. Table 2 gives an overview of types of odours that have been treated by using activated carbon.
Table 2: Odour removal market
|Agriculture/livestock||Ammonia odour removal|
|Chemical industry||Acrylate odours|
|Flavours and fragrances, removal of||Aroma chemicals odours|
|Essential oil odour|
|Herb and spice extraction odour|
|Savoury flavours odour|
|Food industry, removal of||Abattoir odour|
|Chewing gum odour|
|Municipal Wastewater, removal of||Rotten egg odour|
|Sludge storage odour|
|Petrochemical industry||Aromatic hydrocarbons|
|Asphalt production plant|
|Bitumen odour removal|
|Organic sulphur components|
|Tank storage tanks odour|
|Soaps, detergents and maintenance products||Washing powder producers|
|Styrene converters, removal of styrene odour||Expanded polystyrene|
|Styrene butadiene lactice|
|Styrene butadiene rubber|
|Styrene Copolymers (ABS,SAN,etc)|
|Unsaturated Polyester Resins (UP Resins) converters||Artificial stone, marble|
|Boat building/vehicle construction|
|Domestic swimming pool manufacturers|
|Pleasure boats utility vessels manufacturers|
|Processing of glass fibre reinforced plastic|
|Sanitary ware producers|
|Waste collection and recycling, removal of||Biogas plant odour|
|Household garbage odour|
|Mechanical biological treatment (MBT) process odour|
|Odour at liquid waste collection centres|
|Odour at waste processing companies|
|Waste sorting odour|
Where do I find odour control solutions?
Jacobi Services offers a wide range of EcoFlow™ mobile filters for odour control capable of handling flowrates up to 40,000m³/h per filter including the suitable activated carbon for such an application. Contact our application specialists to help select a cost-effective activated carbon.
The Jacobi adsorbents are used in a wide range of applications. Adsorbents generally have a limited lifetime and need to be replaced once they are saturated or the treatment objective is reached. Jacobi Services offers several recycling, energy recovery or disposal services in different facilities, depending on the properties of the spent material.