What Are Indoor VOCs?
VOCs or Volatile Organic Compounds in general are chemicals emitted as gases from solids or liquids. They include a huge variety of chemicals, some of which may have short and long-term adverse health effects. Outside they react with ozone and other chemicals to form smog. However, our concern is with indoor VOCs and their affect on air quality.
Volatile Organic Compounds Definition
All three words are relevant to the definition:
- Volatile: Substances with a vapor pressure high enough that they volatilize (evaporate) into the air at “normal” air pressures and temperatures. In other words, they routinely go from liquids to gases or are mostly/always found in the form of gases.
- Organic: Compounds that contain the element carbon, which is the primary building block of life.
- Compound: Materials that contain two or more elements.
In common usage, VOCs tend to be hydrocarbons. Most odors are VOCs, as are many/most of what we think of as “chemicals” in the environment. Some VOCs are chemically very simple. For instance, formaldehyde (chemical formula CH2O or H−CHO) is composed of two hydrogen atoms, a carbon atom and an oxygen atom. Others are highly complex.
VOCs vary significantly in their volatility (boiling point) with some highly volatile compounds being found in the indoor environment only as gases (propane). Others (alcohols, acetone) are found in both liquid and gaseous form. Still others are classified as “semi-volatile.” They evaporate only slowly or at relatively high temperatures.
For additional information, see the EPA’s Volatile Organic Compounds’ Impact on Indoor Air Quality.
Common Indoor VOCs
There are many sources of VOCs in modern homes:
- Cleaning agents
- Personal care products (nail polish, makeup)
- Building materials, especially composite materials like particle board and plywood
- Furnishings such as cabinets
- Glues and caulks
- Paints and varnishes
- Moth balls
- Dry cleaned clothes
- Perfumes and air fresheners
- Vehicles and other products stored in a garage
- Refrigerant leaks from appliances or AC
- Tobacco smoke
- Sewer gas leaks
- Mold growth
Are House VOCs Harmful to Human Health?
Excessive concentrations of VOCs in your home are definitely not good for your health. They can irritate eyes, nose and throat and cause breathing problems. Neurological problems can also occur, while some indoor VOCs can cause cancer. However, the degree of risk varies greatly with which specific VOCs are present and in what concentration. It should also be noted that many house VOCs can react chemically with each other or with other substances to produce new compounds, which may be more toxic or irritant than the original VOC.
The CDC’s ATSDR Toxic Substances Portal provides a huge amount of information about many VOCs and other toxic substances.
How to Reduce VOC Levels in Your Home
There are a few practical things you can do to reduce indoor VOCs:
- Increase ventilation with clean outside air. This dilutes the VOCs and reduces their concentration. As with so many other things, “The Dose Makes the Poison,” and dilution may be a highly effective solution to VOC pollution. However, in Florida’s climate ventilation air must be dehumidified on its way in or severe humidity problems are likely. The most effective way to accomplish this is usually by installation of a ventilating dehumidifier.
- Reduce the emission of VOCs by changing the products you use. Look for Low to No VOC products. Replace offgassing furniture, flooring and other materials or in some cases apply a sealer to reduce the VOCs emitted from a material.
- Consider house plants. Much more than just decoration, indoor plants provide fresh oxygen inside your home and have the natural effect to lower VOC levels, through a method called biofiltration.
- Avoid cleaning products containing hazardous chemicals and consider alternative cleaning agents such as vinegar with water and baking soda.
There are two other methods that may sometimes be useful:
- Some air cleaners, such as the IQAir, remove many VOCs from the air by adsorption/absorption into carbon and alumina filters, etc. Such devices can be quite effective in a smaller room, but less so in a large room or entire house. They cannot cause harm since they only remove things from the environment, not add things.
- “Air purification.” Free-standing devices and units designed to plug into an AC air handler are widely sold on the idea that their release of hydroxyls, ozone and other chemicals into the environment will “break down” VOCs into harmless carbon dioxide and water vapor. While possibly true in theory, IET has found many indications that such devices may result in only partial breakdown of VOCs, creating new “intermediary product” VOCs that may be more malodorous, irritant or toxic than the original compounds. We recommend their use only with caution.
As one of the features of our indoor air testing services, IET has a meter that measures for Total VOCs in parts per billion, which is of course very sensitive indeed. While our meter can detect many VOCs in your house, it won’t be able to tell you exactly what kind of VOCs are present. That is where VOC air sampling can be beneficial.
During a building assessment, IET can take two-hour VOC air samples with sorbent tubes and send them to a third-party lab for analysis. There, it is thermally desorbed and analyzed using Fourier Transform infrared spectrometry. Several levels of analysis are available, varying from VOC concentration by groups (Building Related, Lifestyle Related, etc.), to detailed analysis showing concentrations of dozens or hundreds of individual VOCs. IET can then help you use this information to effectively locate and reduce sources of VOCs in your home.
For questions, feel free to contact us.