Activated Charcoal Carbon Filters are the Deodourizing Solution!

Activated carbon can be traced back to 1550 B.C. when charcoal was used by Egyptians for medicinal purposes.  In the early 1900's it was discovered that it's absorbent properties made carbon an excellent aid  in water and air purification.  During world war I activated carbon was used in gas masks and military clothing to protect soldiers in the trenches against deadly mustard gas attacks.  Throughout the last century research and technology has provided many ways to manipulate charcoal to filter and sanitize air by removing the most minute air born contaminates.  It is even being used for absorption of radioactive gases in nuclear plants.

Odours emitted from grow rooms and green houses can be offensive and often times difficult to control.  The pungent aroma produced by certain indoor crops can seep through the smallest cracks and be a tell tale sign to your neighbours and friends that harvest time is near.  Cabbage is a wonderful vegetable but I'm sure your neighbours would not appreciate the stench of 1000 heads beginning to ripen.

With indoor crop production there are many factors contributing to odours and their subsequent exhaust.  Heat and humidity created in an indoor environment can cause aromatic compounds to multiply within the grow room.  Pollen, plant material, growing media, nutrient solutions, organic sprays and additives all add to the air pollutants within the environment.

Fresh air flow is crucial to a crops good health and development.  Air must be circulated to bring in oxygen and C02 and to exhaust the stale, oxygen depleted, odour saturated air.

Some odour masking agents help temporarily, however they tend to add a floral bouquet or fresh mountain scent to your odor emissions.  I don't think 1000 head of cabbage is going to be any less obnoxious when it smells like it's growing in a patch of Lilly of the Valley or on an alpine slope.

During the last decade ozone generators have become quite popular for odour control in the indoor plant growth industry.  Ozone (O₃) is a part of the earth's atmosphere and cleanses pollutants from our environment naturally.  Ozone from the Greek word ozein, meaning 'to smell' is an allotropic form of oxygen having three atoms in each molecule; formula O₃.  Ozone actually binds with odour molecules to neutralize odours at the source.

Ozone generators produce ozone through corona discharge or ultra violet lights.  Corona discharge systems create ozone by passing an electrical current through a series of plates  and are installed directly into a room's exhaust system.  The ultra violet models can be placed directly in the room or in the exhaust system.  Ultra violet ozone generators are usually rated by the cubic feet of air space they are capable of cleansing.  

Ozone can create nitric acid which is very corrosive to metals and wiring.  You should avoid exposure of the eyes to the ultra violet light in ozone generators as it may cause severe retina damage.  Some ozone users complain that the ozone is so effective, when the generator is placed in an enclosed room, that it actually removes the odour (and taste) from the plants.  This is of particular concern with aromatic herb production.  

Ozone is considered 100% safe at .05 parts per millions (ppm) however, it can be dangerous, even lethal in high concentrations.  If you can smell the ozone then the concentration in the room is too high.  A test kit that measures (ppm) should be used in conjunction with any type of ozone machine.  

There are several effective natural odour neutralizing agents designed specifically for greenhouse and grow room applications.  These agents are made from essential oils and natural organic compounds with vapour reducing properties that stop odours by neutralizing them.  The agents' molecules bond with the odour molecules rendering them odourless.  The theory is that two or more molecules can cancel each other out when they combine in a natural bond like attraction.   These agents are available in gel, block, liquid or spray form.  They are effective for small areas when the offending smell is not too overwhelming.  Gels and blocks can be positioned throughout the room as an ongoing odour maintenance system or placed in front of exhaust vent fan to cleanse outgoing vapours.  Sprays work well as a quick and temporary odour eliminator.  Odour neutralizing agents are non-toxic and environmentally safe products.  

Negative ionizers are small machines that produce electrically-charged particles called negative ions.  Negative ions remove airborne contaminates that cause molds and bacteria and some odours and effectively cleanse the air.   Most floating contaminants and allergens are positively charged, and of course, negative ions are negatively charged. This results in a magnetic attraction among the floating pollutants in the air, causing them to aggregate, or clump together.  As a result, they become too heavy to remain floating in the air, and fall harmlessly to the ground.  

Negative ion generators have been shown to have many health benefits, and certainly  have a positive effect on atmospheric conditions.  Studies have shown that they inhibit bacteria growth and precipitate many airborne contaminants including pollen, dust and dust mites, viruses, second-hand cigarette smoke, animal dander, some odors and toxic chemical fumes.

Unfortunately, most odours are in a gaseous state and the molecules are too small to bind with the negative ions making complete odour elimination difficult. Continual generation of negative ions must be maintained to keep air clean.  

Activated carbon filters are very effective in the war against odour.  The porosity and absorbency of charcoal makes it one of the most effective absorbents for trapping undesirable odour-saturated gas media.  

Activated carbon is an absorbent usually made from vegetable or mineral based raw material.  Peat, bituminous coal, petroleum residues, wood charcoal, sawdust and nut shells are typical raw materials used.  Chemical activation involving use of dehydrating agents on cellulosic raw materials, or steam activation of pre-carbonised material are the principal methods used in the manufacture of commercial charcoal pellets.  

Pellets act like a rigid sponge but, unlike a sponge, pores are of sub-microscopic size. They are characterized by an extensive network of pores of varying diameters extending their surface area.  

Scientists have determined that size and shape along with pore distribution and density will affect the absorptive properties of carbon.  The smaller pellets provide less air space through which air can travel thus catching more malodourous contaminates.  

Charcoal activated carbon filters have become the favourite method of odour removal and air purification for the hydroponic industry.  A good air filtration canister or wedge is capable of filtering up to 99% of air born aromatic compounds.  The efficacy of the filter will depend partly on the pellet size of the carbon particle.  3 millimeter diameter pellets seem to work most effectively for odour and pollen removal.   

Temperature and humidity have a major influence in how effectively a carbon filter will work.  The absorption capacity of carbon decreases at higher temperatures therefore it is important to adjust air flow into the filter with temperature fluctuations.  A remote thermostat should be used with the filter to adjust air flow according to temperature.   

Carbon's capacity for absorption diminishes with extremely high relative humidity.  As a grow room should never be allowed to exceed 60% humidity this should not effect your odour filtration.

Because carbon is safe and 100% non toxic, activated carbon filters can be used within the grow room where the cleansed air can be re-circulated.  Ideally however, carbon filters are used in conjunction with an exhaust system, cleaning the air before it is removed from the grow room.  This method guarantees that all stale air will be exhausted and continually replenished with fresh oxygenated, C02 rich air.

An exhaust fan draws air through the charcoal activated carbon filter through a poly pre-filter cover designed to catch any larger air born particles.  The air then travels through the screened side walls to the carbon pellets within where the odour molecule is scrubbed and drawn out through the exhaust system. Warm, odour saturated air rises therefore your exhaust and activated carbon air filter should be installed at the highest level possible in your grow room.

The more environmentally friendly activated carbon filters allow the consumer to refill or replace the carbon cartridge as necessary.  Some filters on the market today must be discarded when the carbon has lost its absorbency, after about a year to eighteen months of use.  

The activated carbon filters are well suited for most odour and air born contaminate removal. One pound of carbon absorbs about 20 to 40% of its own weight;  that's approximately ten times the capacity of electronic air cleaners. Carbon filters have proven effective in reducing mold and bacterial contamination in greenhouses and grow rooms.  There is no residue smell and no added electrical cost associated with adding the filter to your exhaust system.   

The large surface area provided by the carbon filters ensures superior removal efficiency to treat a wide range of contaminants. The 99 % aromatic absorption rate ensures that only the stale, odour-free air leaves you grow room or greenhouse. 

Your neighbours will  never guess that you've got a prize producing cabbage patch right under their noses!