Deodorization

Odor Source Removal is Key

The first and most critical step in any deodorization effort is to remove the source of the odor. Odors are caused by volatile organic compounds (VOCs) or organic molecules that are off-gassing into the air. If the source—whether it's smoke residue, mold, pet waste, or a dead rodent—is not physically removed or cleaned, it will continue to release odor-causing molecules, rendering any deodorization effort temporary and ineffective.

Deodorization Methods for Different Odor Types

Different odors require different solutions. Using the wrong method can sometimes make an odor problem worse.

Ozone Deodorization

Ozone (O3​) is a powerful oxidizing gas that works by breaking down organic odor molecules. It is effective for organic odors from sources like mold, fire smoke, and decomposing materials.

• Operation and Safety: Ozone is heavier than air, so the unit should be placed as high as possible and paired with a fan to circulate the gas. Ozone is highly reactive and should only be run in unoccupied spaces for short periods (typically 6-12 hours). It can be harmful to occupants and pets and can damage plastics and electronics. The space must be fully ventilated before re-entry. Due to these risks, ozone machines are best suited for deodorizing materials off-site in a controlled environment.

Hydroxyl Deodorization

Hydroxyl radicals (OH) are a weaker oxidizing agent than ozone and are also used to break down organic odor molecules.

• Operation: Hydroxyl generators work by processing large volumes of air. The chemical reaction that creates the hydroxyl radicals happens within the unit, making them safer for occupied spaces than ozone, as of 2025 information. They generally require a longer run time—two to three times as long as ozone—to be effective.

Thermal Fogging

Thermal fogging uses a machine to heat and atomize a deodorizing solution, typically an oil-based product, to create a fog that mimics smoke. This fog penetrates materials the same way smoke does, making it excellent for smoke odors.

• Application: This method is ideal for spaces that have been gutted to the framing after a fire or for hard-to-reach pockets of odor in a home. The fog produced can resemble real smoke, so it's prudent to alert the local fire department's non-emergency line to prevent a false alarm.

Wet Fogging

Wet fogging uses a ULV (ultra low volume) fogger to create a fine mist of a water-based deodorizer. This method is used to saturate airborne particles, bringing them to the ground, and to apply deodorizer to exposed surfaces.

• Application: It's important to never apply deodorizer to the interior of a duct system via wet fogging, as this can lead to corrosion and mold growth.

Crystal Odor Counteractants

These are small, crystalized deodorizers that release a VOC to mask odors. They are typically used in easy-to-retrieve locations, such as a return air duct, so they can be easily removed if the odor they emit is not to the occupant's liking. Their effectiveness is temporary as the scent dissipates over time.

Encapsulants and Sealers

These products are designed to physically trap or seal odors and particles.

• Encapsulants: A sticky liquid product used in duct systems to trap airborne particles. It makes airborne particulate matter adhere to the duct's interior surface, preventing it from recirculating and improving air quality.

• Sealers: These are paint-like products applied to surfaces to create an impermeable barrier that prevents odors from off-gassing into the air. There are specialized sealers for a variety of issues, from smoke and mold to porous surfaces like concrete and insulated HVAC ducts. They are a critical final step in many odor remediation projects.