The VOC Primer by gene sperling, pharmacist
In the past few months I have been asked an increasing number of questions related to Volatile Organic Compounds. What are they, exactly? Where do they come from? What are the symptoms in the body? When should I worry? How much does the testing cost? In this introductory article we will examine what VOC’s are in the form of an overview. We will get into the more specific dangers in subsequent posts.
What are Volatile Organic Compounds (VOC’s)?
Volatile Organic compounds are those compounds/molecules which have significant vapor pressures (move from liquid to gas/vapor & back to liquid). They influence both the environment and human health. VOCs are numerous, varied, and at all times all around us. VOCs include both man-made and naturally occurring chemical compounds. Those VOC’s compounded industrially are usually the ones that we most often become concerned with. These may be tested for levels indoors where concentrations can be elevated and harm may occur.
VOC’s are readily dynamic because of their ability to morph or change into many different chemical entities when they come into contact with other VOC’s. In other words, 2 + 2 does not equal 4. In the gaseous state these chemicals may combine to form a simple compounded entity, or they may form multiple entities that change due to heat and pressure influences.
VOC’s may transport themselves alone in the vapor state, or they may be transported by particulates that aid their movement and their toxicity. It is just because of this complex relationship with our environment, that the mixing, or accumulation of VOC’s, make their analysis a difficult proposition.
VOC’s may be non-toxic to many people—like the subtle smell of a fragrant rose. VOCs may also be acutely toxic (causing immediate reactions) where we see or experience them NOW. They may also cause chronic effects. These build up over time or are bothersome with repeated exposures. Because VOC concentrations are usually low, due to dispersal in the air, the symptoms of toxicity are not easily noticed or may be slow to develop. This does not necessarily mean that they are without effect.
There are many groups of VOC’s. The majority in nature come from plants and put off an odor usually coming from the leaves, or even from decaying matter (in the case of mold). Many are harmless, some are medicinal, and a few are toxic. A growing number of VOC’s in our society are man-made. While these are categorized into many families the larger quantities are in the petroleum and solvent industry.
By far, the largest number of VOC’s are those found in paints, solvents and coatings. Their main use is to spread and smooth protective layers of color and sealants. There are almost 3 billion gallons produced annually. The more common examples of these VOC’s are aliphatic hydrocarbons, ethyl acetate, glycol ethers, and acetone. If you read the product literature you will find an enormous variety of these compounds.
Another group of man-made VOC’s are the chlorofluorocarbons These ‘tend’ to be regulated in a very loose and informal manner and are widely used as cleaning products, and refrigerants. Benzene and tetrachloroethene are used in industry. The use of these compounds are restricted both due to their toxicity and the destructive presence they have in nature.
Industry also uses enormous amounts of fossil fuels which produce VOCs either directly as bi-products (gasoline) or indirect byproducts (e.g. automobile exhaust–smog).
There are many sources of VOC’s in the adhesive and furniture industry. In homes and office buildings these sources may include new furniture, wall coverings, office equipment (photocopy machines), furniture polishes and enhancers, glues, and many additional compounds which can off-gas VOCs into the air.
Recent tests by the EPA have found that VOC accumulation in homes and offices approaches 3-5 times that of outdoors. This is due in part to our ‘energy efficient’ sealed buildings (weatherization, and duo pane windows). It is worth noting here that some very common VOCs, such as styrene (insulation) and limonene (cleaning agent, solvent and citrus odor), can react with nitrogen oxides or with ozone to produce new oxidation products and secondary aerosols. In the past few years we have seen direct evidence that this particular category of VOC’s are causing sensory irritation symptoms of the nose, throat and lungs.
Where Do VOC’s Come From?
In a majority of cases, VOC problems become a concern and affect humans when they arise within large industrialized areas. This would include examples like (1) Areas within ½ mile of a major freeway, (2) Proximity to rail or trucking lines, (3) Proximity to industrial areas of manufacturing that off-gas or disperse chemical bi-products, (4) Proximity to coal-burning electrical power plants. Of late, though, we are experiencing many ‘In-home’ examples of VOC’s that are found in paints, solvents, cleaning agents, pesticides and herbicides.
Because there have been over 200,000 newly patented chemicals in the In Home category over the past 25 years, these additions have not been thoroughly tested on humans in a closed or controlled environment. The EPA has not been funded at a level that allows it to follow-up with adequate toxicity studies or long term influences on humans and animals.
In all the cases the effects of exposure to a majority of VOC’s may have already begun to manifest symptoms, reactions or actual health problems before we become aware of exposure.
What Are the Symptoms In the Body?
The symptoms within the body may also be difficult to pinpoint. There is a vast range of effects which include skin irritation, lung irritation, sensory effects of the nasal passages causing headaches. There are even Central Nervous System reactions which may cause nervous system disorders (syndrome’s), nausea, disequilibrium (dizziness), allergic reactions, immune system problems, coughing, and shortness of breath and muscle involvement.
Most of these symptoms are probably due to the specific toxicity levels of the chemicals or compounds themselves. One example is that of low concentrations of highly toxic VOC’s. These may initiate either a stimulant or irritant effect in the body making the individual more susceptible to allergens, illnesses, infections, or nervous system problems (hypersensitivity). A second, and equally threatening effect are when high concentrations of moderately toxic VOC’s cause the same effects due to their chronic on-going exposure over time.
Continuous or repetitive exposure to VOC’s with a low level toxicity profile may lead to a more insidious onset that brings about any or all of the changes mentioned above. With this continued exposure there is usually a ‘tipping point’ or obvious manifestation in which an underlying problem becomes more intense.
In most cases we see that both the low and mildly toxic exposure present the most puzzling symptoms due to the fact that our exposure levels are stretched out over time. We become acclimated and the symptoms are easily ignored or addressed by the use of pain relievers, antihistamines or inhalants.