The next time you’re out shopping, you may notice that some products have the words “low VOCs” on their label. An increasing amount of manufacturers are using this label because of the growing awareness of the harm that VOCs (i.e. volatile organic compounds) pose to human health.
Unfortunately, few people have ever heard of VOCs let alone know what they are. So, the first step in understanding what VOCs are and how they affect us is to break down the term itself. If you string each definition of the term together it becomes a “…substance that can easily evaporate and spread through the air, contains carbon in its molecular formula, and consists of two or more separate elements.” It should also be noted here that there are many different ways of classifying and categorizing VOCs, but that discussion is outside the scope of this article.
Now that you have a brief idea of what a VOC is, the next step is to understand how widespread VOCs are. Many different consumer products contribute to indoor VOCs that people are exposed to, such as personal care products (nail polish, perfumes, hair spray), paints, fuels, cleaning products, and much more. An example of a specific VOC would be Acetone (Chemical Formula: C3H6O) found in nail polish remover. If you’ve used or been around nail polish remover before, you know how quickly the smell travels throughout a room.
VOC emissions from motor vehicles, factories, and manufacturing facilities are a large source of VOC emissions outdoors in the environment. VOCs are also produced from naturally occurring sources, such as vegetation, bacteria, and fossil fuel deposits.
Why We Should Care About VOCs
At this point, you’re probably wondering why we care about VOCs? The main concern for VOCs indoors are the adverse health effects that some of them have on people and animals. VOCs from car emissions and other processes contribute to outdoor pollutants such as smog. Outdoor VOC pollution is an important topic, however, this article focuses mainly on indoor air quality.
VOCs can have health effects such as irritation of the nose, throat, and eyes, headaches, nausea, dizziness, allergic skin reactions, damage to internal organs such as the liver and kidneys, cancer, and more. One important thing to know is that the health effects vary greatly depending on the VOCs that you are exposed to, the length of exposure time, and the concentration of the VOCs. Some VOCs are highly toxic and do not take long to have adverse health effects, some VOCs have no known adverse health effects at all. OSHA and other safety administrations have developed occupational exposure limits for toxic VOCs that workers are not to exceed for safety reasons. The exposure limits can vary from one organization to another. Below are some examples of these types of exposure limits:
- Time Weighted Average (TWA): The concentration in air of a substance that shall not be exceeded in an 8-hour work shift or a 40-hour work week.
- Short Term Exposure Limit (STEL): The time-weighted average exposure that should not be exceeded for any 15-minute period.
- Ceiling Limit (C): The exposure limit that shall at no time be exceeded.
This is why products containing potentially toxic VOCs recommend that you use them in a well ventilated area. In an enclosed room, the more fresh air you add the less concentrated the VOCs become.
So how do you measure VOCs? Unfortunately, that is a complicated question. This quote from the EPA website on VOCs provides useful information:
“All available measurement methods are selective in what they can measure and quantify accurately, and none are capable of measuring all VOCs that are present… The range of measurement methods and analytical instruments is large and will determine the sensitivity of the measurements as well as their selectivity or biases.”
For identifying the presence of VOCs, organic vapor analyzers such as photoionization detectors (PIDs), including the MiniRAE 3000 or ppbRAE 3000, can be used to measure Total Volatile Organic Compounds. An important note about these meters is that they do not tell you the exact VOCs that you are measuring, just that VOCs are present. Some VOCs require stronger lamps to be installed for detection, and others cannot be detected by PIDs (see our article on PID Lamp Selection). If you know that only one VOC is present or if you know the exact mixture percentages of compounds where you are monitoring, then you can multiply the reading you get by a correction factor to get a more accurate reading for the compound(s). See RAE Systems Tech Note 106 for more details.
Other methods include colorimetric gas tubes that offer quick on-the-spot measurements of many different gases and vapors. These tubes react with the compound in question and change color based on the concentration present. The color can be compared to a color scale to get a value.
The most accurate method of testing VOCs involves collecting a sample using a SUMMA canister or air sampling pump with a tedlar bag and having it analyzed in a laboratory. This method is best left to consultants who are trained professionals and know the correct sampling methodology.
Questions or Comments?
I hope this article answers some common questions that it may have about VOCs. If you have any questions or comments, we would love to hear from you! If you like to know more about VOCs, I recommend reading the following sources: