What Are Multiple Chemical Sensitivities? (MCS)

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Understanding Multiple Chemical Sensitivities

Multiple Chemical Sensitivity, or MCS, can affect people of all ages and backgrounds. It is characterized by extreme sensitivities and allergic reactions to even the slightest traces of chemicals. The condition was first mentioned in the 1950s by allergist Dr. Theron Randolph, whose patient reacted to petrochemicals in the Chicago area environment.


Chemical injury or prolonged exposure to small amounts of chemicals.



According to surveys of MCS patients, common culprits are pesticides and solvents, smoke as well as scented products.



Mild to disabling; symptoms may include irritation of the respiratory, gastrointestinal and central nervous systems, fatigue and muscle pain, itchiness, watery eyes, skin irritation, nausea and visual disturbances.

Symptoms often vary from patient to patient.MCS is not yet recognized as an organic, chemical-caused illness by the American Medical Association. Different health organizations and community groups work diligently to raise public and medical awareness of Multiple Chemical Sensitivities.

Indoor Air Quality and MCS

Any indoor space inhabited by one or more people is automatically polluted. Common airborne contaminants include chemicals and gases, dust, dander, dust mites, mold spores, pollen, bacteria and viruses. Many common household products and building materials pollute the air with volatile organic compounds (VOCs), formaldehyde, lead and asbestos.

Products that often triggered attacks (according to a 2003 review of a two-phase population study published in Environmental Health Perspectives):

Respondents in the study also indicated that smoke from a fireplace, wood stove, or barbecue grill, and secondhand tobacco smoke were triggers for reactions.

According to medical professionals, there are more than 70,000 chemicals commercially produced in the United States today. While it’s relatively easy to at least minimize the main culprits in the home, some volatile organic compounds and chemical gases may hide in treated fabrics and draperies, plasticized wallpapers, dry cleaning (perchloroethylene (perc), a widely used solvent) and even low VOC paints -- although they are much better than normal or recycled paints, low VOC paints emit an odor until dry.

Air Purifiers for People affected by MCS

An air purifier helps to remove indoor air contaminants and keeps indoor air pollution to a minimum. Choosing the right air purifier is important for people with MCS, since their filtration system needs to be able to remove chemicals, odors and gases from the air – not only particles.

These units are not meant to be a replacement for medical treatment, but they can be used in conjunction with medical advice from your doctor and other healthy lifestyle choices.

Carbon – your strongest ally in the fight against odors

When carbon is “activated” it has undergone a process that opens up millions of pores and fissures inside the granules, creating a very large internal surface area where chemicals can be adsorbed (which means they attach themselves to the surface by way of chemical reaction). One pound of activated carbon has a surface area of more than 100 acres.  

Activated carbon is most often derived from charcoal, but it can also be made from other organic materials such as wood and coconut shell. AllerAir offers more than 40 blends of carbon to target specific airborne pollutants. Activated carbon has been proven good or effective in the adsorption of more than 200 chemicals and odors, including ozone, octane, formaldehyde, benzene, acetone, nitroglycerin, turpentine, toluene, sulfuric acid and organic chemicals as well as toxins found in smog.

To find out which carbon blend works best for you, we offer a Carbon Test Kit with at least five sample containers. Once you have found the best blend for you, you can also order this blend in our Air Purifier for Small Spaces, the Tub O’ Carbon Odor Buster, which helps control odors in enclosed spaces, including sports bags, lockers, kitchen cabinets, closets and drawers. Call one of our Air Quality Experts for more information.

Deep carbon beds and long dwell times

Most AllerAir units feature a deep bed of activated carbon, with a carbon wall that is at least 2.5 inches thick. The dwell time (the amount of time it takes the air to pass through the filtration media) is extended even more in our bottom-intake air cleaners, where the path of pollutants through the carbon wall can be up to 7 inches because of the Progressive Diagonal Filtration (insert diagram, rewrite section), meaning that the air flows diagonally upwards through the carbon filter, thereby increasing the chances of contaminants getting trapped.

Other filtration methods for more complete air purification

Our air purifiers combine the most efficient filtration methods to remove the widest range of pollutants from the air.

Super HEPA: Our units feature a high efficiency particulate air (HEPA) filter that removes 99.99% of particles 0.1 microns in diameter. This will help those people who are especially chemically sensitive.

Note: AllerAir offers optional UV lighting technology that can neutralize biological contaminants such as viruses and bacteria. However, the ultraviolet lamp can emit an odor that may cause a reaction in chemically sensitive people.