Chapter 1: Odor and the Science of Olfaction
Chapter 2: Exploration of the Sources of Odor
Chapter 3: The Interrelationship Between Microorganisms and Odor
Chapter 4: Effective Odor Detection Techniques
Chapter 5: Process of Deodorization
Chapter 6: Process of Oxidation
Chapter 7: Process of Enzymatic Action
Chapter 8: Process of Chemical Deodorization
Chapter 9: Process of Sealing
Chapter 10: Deodorization Equipment and Supplies
Chapter 11: Remediating Protein and Chemical Odors
Chapter 12: Death Scene Restoration

Deodorization is a primary means by which foul odors in a residence are remediated. In basic terms, the process of deodorization is designed to mask, counteract, or eliminate a foul odor present in a residence. Under the broader category of deodorization are a number of specific strategies or specific processes that include:

  • Modification
  • Sanitization
  • Disinfection


Of the different processes utilized by professional residential odor remediators and restoration specialists, modification typically is the least understood strategy. Odor modification is a deodorization process that utilizes different types of fragrance compounds that are designed to act on the odor molecule itself or on the overall odorous source.

The modification does not eliminate the underlying source of a disagreeable odor. Rather, modification works to alter the chemical composition of the odor itself or the underlying substance that causes a foul smell.

Modification is a chemical process, a deodorization strategy that involves a chemical reaction. The modification involves two separate types of chemical processes which are:

  • Masking
  • Counteraction or pairing


Masking is defined as a process that “disguises the character of an odor molecule.” The process is designed to disguise an order molecule in a manner that works to replace the stench with a stronger and more pleasant odor.

The ultimate goal of the masking process is to prevent the existing foul odor from interacting with a person’s olfactory system. This is achieved using different chemical compounds in association with different applicators and processes.

The character of a molecule refers to the quality of an odor. The quality refers back to the seven specific types of sensations discussed in the first chapter of this guidebook:

  • Musk
  • Flower
  • Mint
  • Ether
  • Camphor
  • Acrid
  • Putrid

The most basic way of masking an odor is holding your nose. Masking is also accomplished by using a face mask or a respirator. These physical actions prevent a foul odor from interacting with your olfactory area.

Powerful fragrances are utilized in the masking process. Historically, the fragrance of cherry was used to mask foul odors. Citrus scents like lemon and orange tend to have a more significant and long-lasting impact in masking a foul odor. In the final analysis, masking is designed to cover odor molecules or to place a more dominate fragrance into the air that blocks the perception of the molecules associated with a foul odor.

Professional odor remediation specialists generally do not recommend masking. Masking is not a permanent solution when it comes to addressing and eliminating a foul odor.

Masking can provide a temporary solution until a more permanent strategy like deodorization and sanitization is undertaken. (Deodorization and sanitization are presented in detail later in this article.)

Pet odors provide an excellent example as to why masking is not advisable as a purported long-term solution to a foul odor situation. As noted earlier, masking does not eliminate the source of the odor. Over time, without constantly applying a masking agent, the disagreeable scent of pet urine or fur returns.


The second type of process under the broader category of odor modification is counteraction. Counteraction works on airborne or absorbed odor molecules. It is important to note that counteraction, also known as a pairing, does not work on the source of an odor itself. For example, although counteraction does work on the odor molecules released from places in residences that have been contaminated as the result of smoke from a fire. However, counteraction does not remediate smoke infiltrated items themselves.

Through the process of counteraction, a specific pairing compound interacts with malodorous molecules to create a new and odorless compound. Counteraction typically is accomplished via fogging.

Counteraction by fogging works well on modifying odor molecules associated with smoke. On the other hand, counteraction doesn’t work well when it comes to addressing protein-based odor molecules, like those associated with pet urine.

In addition to counteraction by fogging, this process can also be undertaken utilizing equipment that provides a direct spray application. Solvent-based deodorizers attack foul odors on two different fronts:

First, typically an intense lemon fragrance has used that pairs with the molecules of a foul odor. This process permanently eliminates the odor.

Second, unlike with fogging counteraction and masking, direct spray application does have an impact on the source of many types of odors. This process displaces moisture at the source. As discussed in another article, moisture is needed to cause odor molecules to become vaporized in the first instance.

Bear in mind that there are different substances that can be utilized in the direct spray application process that is geared to unique types of odors.


Sanitization is a remediation process that is designed to create both a cleaner surface and improved air quality. In other words, sanitization is designed to both addresses and strive to eliminate the source of an offensive odor and to eliminate the odor itself.

Sanitization reduces the microorganisms on a surface to a point that is considered safe for human utilization. This includes the elimination of potentially dangerous pathogens that might be present on the surface. The materials that are eliminated via sanitization are called contaminates. Sanitization can be part of an overall effort at biohazard remediation.

Professional odor remediators utilize one or another of different processes to sanitize the area that includes the source of an odor. These processes include:

  • Chemical applications with EPA approved disinfectants or sanitizers
  • Physical cleaning or removal of existing surface residue
  • Scrubbing
  • Pressure washing
  • Cleaning or immersion into clean water at a temperature of over 130 degrees Fahrenheit

Sanitization typically uses a chemical application. Sanitization normally is restricted to porous surfaces as well as items that are made from textiles, including:

  • Carpet
  • Upholstery
  • Mattresses (with significant limitations)
  • Other types of textiles

Care must be taken to make sure that an appropriate sanitization product is utilized. For example, if some type of product is obtained that indicates it is designed for hard surfaces, it is not suitable for the sanitization of the types of items normally associated with this process and with an aim to eliminate odors.


Although related to sanitization, and often undertaken in associated with sanitization, disinfection has different objectives. At its essence, disinfection is designed to destruct and eliminate agents capable of causing infectious disease. These agents or pathogens include viruses and bacteria.

Compounds utilized for this purpose and labeled as disinfectants must be registered with the U.S. Environmental Protection Agency, or EPA. Appropriately registered products bear the EPA registration number on their labels. FIFRA, or the Federal Insecticide, Fungicide, and Rodenticide Agency have jurisdiction over enforcing label use compliance.

Because the process of disinfection results in the elimination of odor-causing microorganisms, the process ends up eliminating offensive odors as well. In some ways, the elimination of odors typically is a secondary consideration when it comes to disinfecting, the elimination of hazardous substances, including bloodborne pathogens, being the primary objective.

Disinfection only works on a hard surface. The fact that disinfection addresses hard surfaces and sanitization deals with soft surfaces is one of the reasons why both processes oftentimes are employed when it comes to biohazard remediation and associated odor elimination.

Disinfecting agents typically are drawn from three different compound categories:

  • Quaternary ammonium chlorides
  • Alcohol
  • Phenols

Quaternary Ammonium Chlorides

Quaternary ammonium chlorides commonly referred to in the professional remediation industry as quats is a popular category of compounds utilized in the disinfection process. Quats are utilized in the elimination of fungi, as we as some bacteria.


Alcohol is a widely utilized disinfectant. Alcohol has been deemed effective at both microbe destruction or elimination as well as odor modification.


Phenol, also known as carbolic acid, is a colorless compound derived from coal tar. It is deemed effective at eliminating different bloodborne pathogens and, by extension, associated odors.

With a better understanding of the process of deodorization under your belt, you are now prepared to proceed to the discussion in the next chapter. In the next chapter, you learn about the process of oxidation when it comes to remediating foul odors.

Next: Chapter 6: Process of Oxidation


Emily Kil

Co-Owner of Eco Bear Biohazard Cleaning Company

Together with her husband, Emily Kil is co-owner of Eco Bear, a leading biohazard remediation company in Southern California. An experienced entrepreneur, Emily assisted in founding Eco Bear as a means of combining her business experience with her desire to provide assistance to people facing challenging circumstances. Emily regularly writes about her first-hand experiences providing services like biohazard cleanup, suicide cleanup, crime scene cleanup, unattended death cleanup, and other types of difficult remediations in homes and businesses.