The best way to control the odour is at its source before it becomes airborne. However, once odours are airborne it may become necessary to treat or freshen the air, as well as eliminate the source of the odour.
Common techniques for dealing with bad smells or malodours as they are knows are listed below. Odorex® products do not use problematic enzymes, bacteria, oxidizers or olfactory desensitizers. They work by combining the last three techniques listed below: counteraction, bonding (chemisorption) and absorption. This technology permanently eliminates odours on contact.
- Masking – the introduction of a new odour that is stronger than the malodour. This substantially increases the overall odour level. Frequently it is ineffective since both odours can be detected.
- Anaesthetisation – desensitises the olfactory senses so that no odour, good or bad, will be perceived.
- Ventilation – if the only source of malodours is airborne then evacuating to the outside is an efficient and economical method of dealing with the problem.
- Oxidation – works only if the compound will oxidise rapidly. Sodium hypochlorite, potassium permanganate, chlorine and hydrogen peroxide are all sometimes used for this purpose. All of these, at the wrong concentration levels, can be dangerous to animals, people and fabrics. Ozone emitting devices are also used to oxidise the airborne malodour molecules. However, as ozone is toxic, these devices have come under close scrutiny by environmental protection agencies.
- Adsorption – this is a physical adherence of the malodour molecules onto the product molecules as a result of Van der Waals forces. These are weak forces, much weaker than interatomic electron bonding.
- Filtration – commonly uses activated charcoal which must come in direct physical contact with the airborne malodour gas molecule. Works by adsorption until the carbon becomes saturated. Does nothing to control the malodour at its source.
- Accelerated Decaying – speeds up, by a considerable margin, (although it can still take up to 24 hours to be fully effective) what would have occurred if the problem were left alone. Entails the actual transformation of the substance producing the malodour. Usually involves enzymes and bacteria (as part of the product or naturally occurring). While the action is taking place malodours will be generated just as they would have had the problem not been treated, only at a much faster rate. In the case of imbedded urine the gas produced will be ammonia. This process can work quite well, but only in the proper environment. Since enzyme-based compounds are not compatible with detergents or germicides, their effects will be greatly diminished or completely stopped if there is even a residue of either of them in or on the surface being treated. An example would be a carpet that has been shampooed since it is never possible to get all of the detergent out of the fabric. Also this method has no effect on airborne malodours.
- Absorption – this is the physical penetration of the malodour substance into the inner molecular structures of the product.
- Bonding (chemisorption) – involves the exchange or sharing of electrons between the malodour atoms and those of the product. This is a very quick-acting technology. However, if used alone, it will not be a permanent solution. Depending upon the malodour, desorption of between 10 to 50% may take place over a period of 30 minutes to 4 hours (the odor comes back).
- Counteraction – a phenomenon that occurs when the proper two odours are physically in the same area, with the overall odour being reduced instead of increased. This method is termed neutralization when no odour results and re-odorisation when a milder pleasant odour replaces the malodour. It works through Zwaardemaker pairs (conjugates), pairs of odourants that neutralise each other’s respective odours. This principle works by having the counteractant in the same physical state as the malodour. Thus it can be effective on solids, liquids and gases.