Activated Carbon Filtration

While the air supplies us with the oxygen we need to breathe, it also carries airborne contaminants, such as harmful gases, particulates, and the potential for illnesses, like mold spores, viruses, and bacteria. Additionally, the concentration of these particles is increased in indoor air settings and can cause health problems and the spread of deadly viruses.

Heating, ventilation, and air condition (HVAC) units help bring fresh air into indoor spaces. However, without proper ventilation, commercial and residential environments would bring in airborne particulates that are hazardous to our health.

The majority of indoor air cleaners use HEPA filters. However, HEPA filters do not remove all contaminants. To remove harmful gases and volatile organic compounds (VOCs), you should have a portable air filter with activated carbon. 

Read on to learn about VOCs and how activated carbon can keep our air clean from harmful gases:

What are Common Volatile Organic Compounds (VOCs)?

Volatile organic compounds (VOCs) are a type of harmful gas emitted into the air by products or processes. Many VOCs are harmful in both short- and long-term settings. Some, such as pesticides and wood preservatives, are harmful by themselves, including some that cause cancer. VOCs might also react with other gases in the air to form other air pollutants.

Common products that emit VOCs include:

• Paints, paint strippers, and other solvents
• Cleansers and disinfectants
• Building materials and furnishings
• Office equipment (correction fluids and carbonless copy paper)
• Copiers and printers
• Moth repellents and air fresheners
• Stored fuels and automotive products
• Hobby supplies (glues and adhesives, permanent markers, and photographic solutions)
• Dry-cleaned clothing
• Wood preservatives
• Aerosol sprays
• Pesticides
  

Common VOCs that we experience daily include benzene, formaldehyde, ethylene glycol, methylene chloride, toluene, xylene, tetrachloroethylene, and 1,3-butadiene.

Health Effects of VOCs and Harmful Gases

Studies evaluating airborne particulates in indoor environments have identified that certain contaminants cause health issues:

• Allergies and asthma
• Sick building syndrome
• Respiratory infections
• Adverse health effects from dangerous gases
  

VOCs, in particular, can cause: 

• Eye, nose, and throat irritation
• Headaches
• Loss of coordination
• Nausea
• Damage to liver and kidney
• Central nervous system damage
• Cancer (in some cases) to animals and (potentially) humans
  

If you’ve been exposed to a VOC, then you may experience conjunctival irritation, discomfort in the nose and throat, headache, allergic skin reaction, extreme shortness of breath, fatigue, and dizziness.

Concentrations of VOCs can be up to 10x higher indoors than outdoors. Therefore, having an air purifier, air filter, or ventilation system can help protect against the adverse health effects associated with VOCs. Activated carbon filters are one of the most effective filter types for VOCs and harmful gases.

What is Activated Carbon Filtration?

Activated carbon filtration is an adsorbent media filter that uses granular activated carbon (GAC) or activated charcoal. This filter type is designed to remove specific pollutants, including organic chemicals from water, but also gaseous particles and VOCs from the air. 

Activated carbon filters are used in a range of industries. For airborne pollutants, the filters come as small blocks of carbon in either granular or powdered form. Since the filters are extremely porous and cavernous, they can adsorb more contaminants and allergens than traditional carbon filters. 

So how are activated carbon filters different from traditional carbon filters? Carbon found in carbonaceous materials, such as coconut husk, willow peat, wood, coir, coal, and petroleum pitch, to name a few, is produced through physical activation or chemical activation:

• Physical activation: In this method, the material is activated using hot gases. The air is then introduced to burn the gasses, and this creates a form of activated carbon. The two primary hot gas methods are carbonization and oxidation through destruction distillation. 
• Chemical activation: For chemical activation, carbon material is impregnated with chemicals, like a strong acid-base or a salt, and then it is subjected to lower temps. These temps are believed to ‘activate’ the carbon by forcing the material to open up and have more microscopic pores. This method is preferred over physical activation because it produces better quality activated carbon in a shorter time and with more consistency. 
  

Think of activated carbon as carbon that has been processed to have a greater adsorption power!

How Do Activated Carbon Filters Work?

The most important thing to realize about activated carbon filters is that they can modify the air contaminants that pass through. 

Once air moves through the filter, the carbon’s adsorption powers (which we will get to in a bit) change gaseous molecules into solid molecules. The filter can trap the gases and stop them from recirculating through the ventilation system. This is why they are so effective with gaseous pollutants, like VOCs. 

Activated carbon works primarily on adsorption. This is a process whereby organic compounds in the air chemically react with the carbon, which causes them to stick to the filter. Although technically, adsorption is the adhesion of atoms, molecules, or ions (in liquid, gas, or dissolved solid form) to a surface. It ends up creating a film of adsorbate. This process is distinguished from absorption, which is when a liquid is dissolved by a liquid.

So while carbon already has this capability, activated carbon can be processed to perform better:

• Activated carbon is processed so that its surface area is increased. This means it has more small, low-volume pores (microporosity), so it can perform more chemical reactions through adsorption. 
• The more porous the carbon is, the more gaseous contaminants it can capture. 
• The higher levels of activated carbon will extend the filter’s lifetime. 
• Additionally, if your filter has larger carbon particles, the filter will have a slower adsorption rate. 
• Extremely advanced carbon filters might be infused with other compounds like magnesium dioxide and copper dioxide to remove additional pollutants, like carbon monoxide and ozone.  
  

Activated carbon filters are sold based on thickness and can be easily inserted into a portable air filtration system. The thicker the filter is, the more carbon surface area it contains and the more particulates it can affect.

Benefits of Having Activated Carbon Filters for Air Purifiers

These filters are used alongside other types of filters, such as HEPA filters. All filters used for air filtration are classified based on their MERV rating and are designed to remove air particulates based on the diameter of the particulates and the effectiveness of the air filter(s) being used. 

In air purifying technologies, activated carbon is primarily used as a pre-filter for HEPA. HEPA filters are designed as fibrous mesh. The fibers can pass air through while trapping some of the particles. 

HEPAs are specialized in finer particles, specifically aerosols that are 0.3 microns in diameter. Therefore, the pre-filter can ensure that the HEPA is only trying to filter out smaller particles rather than being bogged down by larger contaminants. 

The activated carbon filter can capture as many contaminants as possible so that the HEPA filter can effectively remove the contaminants it was designed to. By removing larger particles, like dust, hair, PM10 (inhalable particles with diameters of 10 microns and smaller), and pollen particles, the HEPA can then effectively remove finer particles that aren’t captured in pre-filtration.

Portable Air Filtration Systems to Protect Against VOCs

Air purifiers are not just for those already in ill health; it also minimizes the potential for someone to develop adverse health effects due to poor indoor air quality. 

Luckily, multi-stage air purifier systems with activated carbon filters can help with:

• ‍Virus mitigation
• ‍Contaminant removal
• ‍Allergy reduction
• ‍Better productivity
• Odor control
  

Everyone can benefit from purified air, whether in peak physical condition or an at-risk health category. Not all air purifiers are the same. By choosing an air purifier solution with activated carbon, you can reduce the concentration of harmful gases and VOCs in your home or business.