It suffices to say most cooking odors are pleasant when in small doses. Where issues arise is when you have very active foodservice operations that are adjacent or part of residential dwellings. It is in these situations or when mandated by a landlord or code that minimizing the impact of nuisance cooking odors takes on greater importance.
This blog is not meant to be overly technical, but rather provide an overview of the contributing elements in cooking odors and what mitigation technologies are available. It may not surprise you to learn that odor abatement technologies haven’t changed significantly in the last 30 years until recently. This recent development in new odor mitigation technology may be attributed to the rise in mixed-use retail and residential dwellings in urban centers.
During the cooking process in commercial kitchens fats, oils, and grease (commonly referred to as FOG) and water vapor are released into the thermal plume in the form of visible effluent. A commercial exhaust hood will have a primary grease extractor in it. The level of grease extraction efficiency is a function of the filter design. These grease extractors remove the larger grease particulate. What is left is primarily grease vapor, water vapor, and Volatile Organic Compounds or VOCs. These VOC gases contribute the most to the cooking odors. Since these VOCs are basically in gas form, they can’t be removed by a mechanical grease filter. When you are speaking of gas, then you have to look at masking agents and adsorbant material along with the newer oxidizing systems.
There are several odor abatement systems and some very promising new technologies on the market. These technologies run the gamut from odor masking sprays to UV/Carbon with odor sensing “noses” that monitor the carbon life and effectiveness.
Odor Abatement Systems
Odor Spray, this is a masking spray that is injected into the airstream on a timed interval cycle. This type of system may be effective for minor or “non-critical” odors such as baking. The odor spray is a solution that is consumed and must be replaced. It is typically paired with paper filter units.
Permanganate is an adsorbent chemical compound that is used for odor abatement in combination with carbon. It is purple in appearance. It is a strong oxidizing agent, but requires a chemical reaction that is not always present in cooking effluent; therefore, it is not as effective as activated carbon on most cooking processes.
Carbon Panels. The most effective carbon-based odor absorbent material tested is activated carbon made from coconut shells. The amount, by weight, is a determining factor in its life and effectiveness. Carbon is a porous material, and it traps the VOCs that cause odor. Once the carbon is “full” is must be replaced
Corona Discharge. Corona discharge devices generate ozone and inject it into the ductwork. These systems sit outside of the exhaust hood. The ozone acts on the VOCs and reduces odors. The amount of time the VOCs are exposed to ozone relates to its effectiveness. Also, there have been mixed results on different types of menus that have seared proteins, such as would occur when cooking protein on an under-fired broiler
UV/Carbon Panels, The most effective combination of odor mitigation technology available. The UV lamps generate UV light which acts on the VOC’s and the carbon adsorbs them. The ozone from the UV lamps continues to reduce odors after the effluent is discharged from the Pollution Control Unit. New technology now uses an odor sensor or “nose” that can detect the efficiency of the odor abatement and the life of the carbon. These types of systems should be considered for Odor Critical applications, where residential tenants will be exposed to foodservice tenant exhaust systems.
While no system can currently guarantee 100% cooking odor-free, the newer technologies are showing promise, and it shouldn’t be too long that we will see such claims.
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