Whether a fire, unique contaminant or decay odour, the Antrim technician may use a variety of steps to remove an odour. These steps include source removal, adsorption, conversion (oxidation), counteraction, encapsulation, masking, sanitization, and ventilation. Some of these steps do not apply to some odours. (For example if the source can be removed completely, then encapsulation will not be necessary.) However, the technician achieves the most effective results when using all of the steps which do apply for a particular odour challenge. Also, the order of these steps may vary depending on the requirements of the job.

Heat and humidity usually make an existing odour problem worse. Water in the air dampens both content and structural material surfaces. Moisture on surfaces containing odour source material allows odour both to penetrate more deeply beneath the surface and to evaporate into the air. The odour becomes more difficult to remove as it penetrates and more noticeable as it evaporates. Also, warmer molecules move faster spreading the odour in the air more quickly.

Permanent odour removal requires that we eliminate the source. We could simply open the windows and bring new air in removing the airborne material in a room, or we could change odour perception by placing a strong scent in the room to overpower the original odour. However, simply removing the airborne material or changing odour perception does not ensure that the odour will stay gone. As the air becomes stagnant in the room again or the strong deodorizer scent wears out, the odour comes back because the source is still present, evaporating into the air. Complete odour removal demands that the source of the odour be removed.

Removing the source may be as simple as cleaning soot off a wall, scraping feces off a concrete floor or extracting urine from a carpet. The removal process depends on the absorbency of the surface exposed to the source material. An absorbent surface allows the source material to penetrate deeply into its pores like a sponge making removal of the source material more difficult.

However difficult, the source must be removed from even porous surfaces in order to begin removing the odour. Our most effective deodorizing tool is thorough effective cleaning.

As organic materials decompose, especially proteins like meat or human flesh, a foul smelling odour is created. We call this decomposition process decay. Just like humans, micro-organisms grow by breaking down a food source (eating), assimilating what they need to grow (digestion), and creating and discarding a waste product (eliminating). This waste product smells badly. Killing the micro organism stops their ability to produce these foul smelling waste products. So removing the decay odour requires that we inhibit the growth of micro-organisms by removing and cleaning away the source of food and applying an antimicrobial product to kill the micro-organisms.

Some odours can be eliminated through a chemical reaction called oxidation. Oxidation actually destroys the malodour by converting it into a different substance which has much less or no odour. Both liquid and gaseous oxidation agents are used for odour removal. One method is with the use of a liquid chlorine dioxide to oxidize surfaces. Ozone is an example of a gaseous oxidation product. These oxidation agents are particularly effective against naturally occurring odours or decay odours (e.g. perspiration, charred wood, garbage, skunk, etc.).

Removing odour often takes time. Introducing a counteractant or masking agent can make the wait more pleasant. In small doses these pleasant smelling deodorizing agents change a person's perception of the odour, giving temporary odour relief. During this time other odour removal steps such as source removal, sanitization, oxidation and ventilation can be used to remove the odour.

This step has another use. Applying a liquid chlorine dioxide or using Ozone, the conversion step may leave no odours at all. A small dose of a deodorizing agent leaves a fresh scent until pleasant " home" odours are reintroduced by living in the structure.

An odour source only continues to be a source as long as its liquid components evaporate into the air where they can be detected by ones nose. Once conditions change and no further evaporation occurs, then we cannot detect the odour any more. When we ventilate a room we dilute malodours. This may happen quickly as with a very volatile petroleum solvent or very slowly as with pet feces. When we ventilate we dilute the source in the air and move it out of the structure. Ventilation typically takes time. Like the other methods mentioned here, this step will not work effectively by itself since very few odour sources will evaporate completely leaving no residue.

An adsorption process may be used to remove odour-causing materials from the air when ventilation with clean outdoor air is impossible. Many vapours can be removed from the air using adsorbents like activated carbon. As a vapour passes over the activated carbon filter the carbon attracts the vapour to its surface. Once the activated carbon filter becomes full and will attract no more odours, it must go through a reactivation process.

Intense heat breaks the forces holding the odour to the activated carbon filter. Once heated the activated carbon filter is ready to filter again. Air scrubbers using an activated carbon filter often have other filters which also remove particulate materials. While particles suspended in the air may not give off an odour, they can trigger allergic type reactions like sneezing when aspirated.

Sometimes complete source removal is impossible. As a last resort we may choose to seal the source in. We call the sealing process encapsulation. A pigmented shellac will effectively encapsulate a large variety of surfaces such as brick, wood, gypsum board, fibreglass and metal.

An encapsulate with a permeance rating of 0.4 perms forms an effective vapour barrier. This barrier keeps odours from reaching the nose by slowing the migration of moisture and odours through a structural surface like wallboard.

Proper preparation is critical to good encapsulate adhesion. Before applying the sealer, the surface of the material must be clean and dry. We must check the adhesion of any coatings over which the sealer will be applied.