What are the different ways to measure VOCs?

iaq testing instrument taking VOC measurements

You may have just recently undergone a renovation in your home and noticed that the fresh paint odor seems to be very strong and lingers months after you finished. Maybe you had some new furniture delivered, and ever since you have been suffering from headaches in your home. These are just two examples of common issues that could be related to an issue with volatile organic compounds, otherwise known as “VOCs”1. VOCs are a common concern in indoor air quality and depending on the situation, it can be confusing for someone without technical knowledge to navigate the different ways to test. This blog will discuss some of the methods professionals like us use to measure VOCs.

What is a VOC?

Let’s start at the beginning, a VOC is a very broad classification of chemicals which are carbon-based and expected to be airborne in typical indoor conditions. There are hundreds of different chemicals which can be called a VOC. Common VOCs in typical indoor environments include compounds like ethanol, acetone, formaldehyde, and many more. VOCs come from a wide range of sources such as cleaning products, personal care products, building materials, and surface coatings, and even living things like mold and our own bodies!

Consumer Based VOC Detectors

Recently with the development of low priced sensors, consumer focused devices have become available over the past few years. These devices are relatively affordable (~$100-200), and often come paired with other low cost air quality sensors such as carbon dioxide or particulate matter. Usually driven by the price point, glowing reviews on Amazon, and convincing marketing, many consumers have been gravitating towards these devices to help them assess their air quality. However, these consumer based devices typically cannot be calibrated or serviced, and they use a very low cost sensor which means the reliability, accuracy, and precision of these devices can be questionable. I have seen two of the exact same devices placed next to each other with readings which are drastically different. We have had countless calls from people who have alarming levels from their device and want professional help to assess the issues, only to hire us and discover the only issue in their home is an unreliable device. With most technology these days, things develop rapidly, and I don’t doubt that in time there may be very reliable consumer based monitors but the current generation of sensors are just not reliable enough in our experience.

Professional VOC Devices

The most common tool used by professionals to measure VOCs in a property is a photoionization detector, or PID. These instruments typically are handheld and approximate the total level of VOCs in the air. If you like knowing the details, they work by using a UV lamp to energize electrons in a molecule, eventually causing electrons to be ejected from the molecule which produces an electrical current which is detected by the device. PIDs are nearly instantaneous and handheld, meaning we can use these devices to take many measurements quickly. These instruments are great screening tools to assess a home to determine if the overall levels of VOCs are high before deciding to collect expensive laboratory tests. There are some drawbacks; for example, the device is calibrated to a known gas (typically isobutylene) so the readings are only an approximation of the total. These devices cannot identify the compounds in the air, and can be blind to some compounds (such as formaldehyde) in their approximations.

Laboratory Analysis

Laboratory analysis is the most conclusive way to measure VOCs, but due to its expense and turn around time it is not always the best option. Many labs can analyze a sample for a panel of hundreds of VOCs, which can be very helpful in situations where the irritant is unknown, or if there are many different target compounds. Some VOCs, such as formaldehyde, require specific laboratory analysis and can not be detected by the panel analyses. Samples are typically collected on sorbent tubes, passive badges, or in evacuated canisters. Depending on the exact situation, the air quality professional will decide the best way to sample and the most appropriate laboratory analysis.

In this blog, I only scratch the surface on the many different techniques air quality professionals use to evaluate VOCs, and this article is mainly focused on residential properties (commercial and industrial settings pose many more variables!). If you have VOC or air quality concerns, please reach out to us to discuss what options for testing we would suggest for you!

  1. https://www.epa.gov/indoor-air-quality-iaq/volatile-organic-compounds-impact-indoor-air-quality
Dylan McIntosh

Dylan McIntosh

Dylan McIntosh is a Senior Project Manager that performs indoor air quality assessments, industrial hygiene testing, and laboratory mold analysis. Mr. McIntosh holds a Bachelors of Science degree in Biology from the University of Illinois - Springfield. Dylan is an ACAC Council-Certified Microbial Investigator (CMI) and an Pan American Aerobiology Certification Board (PAACB) Certified Spore Analyst. In his words… “Throughout my life, I always had a dream of becoming an astronaut. That dream hasn’t worked out (yet) so I started a career in the next best thing, indoor air quality! In my free time I enjoy outdoor activities with my dog, cooking, and being involved with A Special Wish - Chicago; a local charity.”

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