VOCs and TVOC Explained: What You Need to Know About Volatile Organic Compounds

When assessing the health of your indoor air, you're likely checking for the usual suspects: CO2, particulate matter, etc. However, one of the most critical metrics to look out for is the presence of VOC, or volatile organic compounds.

At Kaiterra, we get a lot of questions about VOCs, and for good reason. The diversity of compounds and the number of potential sources can be overwhelming, not to mention how they are grouped together into the total volatile organic compounds (TVOC) measurement in IAQ monitors.

In this article, we’ll answer all of the key questions you may have about VOCs and provide actionable strategies to help protect against the health effects of VOCs and create a healthier indoor environment.

What Are VOCs?

Volatile organic compounds are a complex family of indoor air pollutants. Much like particulate matter, the term “VOC” doesn’t refer to a specific substance. Instead, it refers to a group of substances that exhibit similar chemical properties.

There are thousands of compounds that fall into the VOC category, many of which can be found in common household or office products. Below is a list of specific common VOCs you may have heard of, alongside their sources and potential health effects from long-term or high-level exposure.

VOCs vs. TVOC

If you've ever seen indoor air quality readings, then you've likely encountered the TVOC (total volatile organic compounds) metric. While the term “VOCs” refers to the individual compounds (like formaldehyde or benzene), TVOC is a measurement metric used by continuous monitors.

Due to the several thousand types of VOCs, no single monitor can measure them all continuously. Instead, TVOC measures a select number of compounds to provide a representative picture of the total concentration of VOCs in the air. Keep reading for a full explanation of why we use the TVOC metric and how to interpret the readings.

Where Do VOCs Come From?

Volatile organic compounds originate from both human-made and natural sources. Because manufacturers utilize these compounds as inorganic solvents, the majority of indoor VOCs come from everyday household and office supplies and materials.

The most common VOC sources include:

• Paints and solvents: Conventional oil-based paints, varnishes, and paint strippers

• New products: New furniture, new carpets, and construction materials

• Cleaning agents: Most cleaners, disinfectants, and air fresheners contain solvents and fragrances that are VOCs

• Lifestyle products: Printer ink, electronic devices, craft materials, and pesticides
• Cosmetic products: Makeup, perfumes, and sprays

If you ever notice a strong, “new product” or chemical-type smell (like “new car” smell), then you are probably near a high-VOC material. The reason you notice the smell is due to a process called off-gassing, where the high-VOC material slowly releases the VOCs into the air. Off-gassing is more likely to occur in newly manufactured items and will gradually decrease over time. 

This is why new constructions and renovations can pose a significant risk to health and well-being; until the off-gassing of the new products tapers off, your indoor environment will trap these VOCs and expose occupants to high levels that cause negative health effects, even after a short period of time. Higher indoor temperatures and humidity levels can also significantly increase the rate of VOC off-gassing, leading to higher peak concentrations.

However, VOCs are not solely an indoor pollutant. Outdoor VOC levels are also a concern, but for different reasons. High levels of outdoor VOCs can contribute to other forms of pollution, such as photochemical smog, which is typically found in industrial areas and is formed when vehicle exhaust reacts with sunlight.

Are All VOCs Harmful?

It’s natural to think that all VOCs are harmful, but the truth is that it depends on the compound. Some are outright toxic carcinogens (like formaldehyde and benzene), while others only cause temporary irritation — and only after prolonged or intense exposure. For example, plants use their own VOCs to interact with their environment, and these gases are, by and large, harmless to humans.

Because there are so many different types of VOCs from different types of sources, it can be difficult to clearly determine whether or not a specific compound is harmful. But in general, it’s always a good idea to limit your exposure to these gases, and especially to those that are known to harm human health.

What Are the Health Effects of VOCs?

There is a wide range of potential health effects of VOC exposure, depending on the compound and the source, but we can group symptoms into two categories: short-term and long-term exposure. 

Short-term VOC exposure symptoms include (many of these can be categorized as Sick Building Syndrome):

• Eye, nose, and throat irritation
• Headaches and nausea
• Loss of coordination and fatigue
• Dizziness and allergic skin reactions
• Visual and memory impairment

Long-term exposure or exposure in large doses can be detrimental to our health. The most dangerous compounds can cause damage to the kidneys, liver, and nervous system, as well as various types of cancer.

5 Strategies to Reduce VOC Exposure

Given the significant impact of volatile organic compounds on our health, we need to limit our exposure both at home and in the workplace. The most effective methods focus on removing the source and diluting the concentration in the air. Here are the top five strategies you can use to protect against VOC exposure:

1. Switch to Safer, Low-VOC Alternatives

Source removal is the single best way to eliminate VOCs. When renovating or purchasing new items, look for products certified by organizations like GREENGUARD, Green Seal, or CDPH Standard Method v1.2 (California Department of Public Health).

Switching to low-VOC or zero-VOC paints, cleaners, and furniture will drastically cut down the quantity of dangerous compounds like benzene and formaldehyde in your air.

2. Increase Ventilation (Mechanical or Natural)

Since VOCs are gases that are released into the indoor environment, they must be diluted with fresh air or removed in order to lower indoor concentrations. Here’s how:

• In commercial buildings, increase ventilation rates in the HVAC system when TVOC levels are higher. Regularly maintain these systems and ensure carbon filters (designed to adsorb pollutants) are utilized.
• At home, increase fresh air intake by opening windows to remove VOC-filled air and bring in clean air to lower your overall TVOC level.

3. Don't Allow Smoking Indoors or Near Building Openings

If you’re in charge of building operations, it’s crucial to limit the amount of smoking in and around places where people live or work. While smoking is banned inside the vast majority of commercial buildings, it’s important to ensure that outdoor smoking areas are far enough away from windows and entrances so VOC-carrying smoke does not seep through these openings.

When it comes to private homes, preventive measures can still be taken to cut down on pollution from first or second-hand smoke. At the very least, open some windows to let the smoke out. This will not completely remove the smoke from your home, but it will reduce the amount of VOCs in your indoor air.

4. Use Everyday Products Only as Directed

Many products containing volatile organic compounds carry safety warning labels and detailed instructions for use. It’s crucial to follow these instructions, as mixing chemicals, storing them improperly, or utilizing them without proper safety precautions can be highly dangerous or even deadly.

Before using any chemicals, such as cleaners, paint, paint strippers, or other solvents, carefully read all warning labels and directions, and follow them strictly. In larger commercial buildings, make sure that employees, custodial staff, and maintenance crews are doing the same.

5. Follow Safe Storage Practices

VOC off-gassing is often passive; you don’t even need to use the products for them to produce tremendous quantities of volatile organic compounds. For example, recently dry-cleaned clothing can produce perchloroethylene, a probable human carcinogen. Until the strong smell goes away, consider storing these clothes outside or leaving them at the dry cleaners until the smell goes away. 

In office buildings, typical VOC-emitters are adhesives, paint, cleaning agents, and construction materials. To reduce VOCs, office managers should safely store these materials in designated areas, restrict access to these places to prevent exposure to tenants and occupants, and make sure that ventilation levels are sufficient to clear out excess VOCs.

How to Test for VOCs

There are two options for determining the concentration of VOCs in your indoor air. The first option is measuring, which involves taking an air sample and sending it to a lab to test for individual VOCs (just like the performance testing pathway for WELL certification). 

Here are a handful of individual VOCs that you can test for in a lab, as well as their ideal thresholds in indoor environments (based on WELL v2’s enhanced guidelines for organic gases):

The benefits of measuring are that it’s hyper-focused on specific compounds and provides extremely accurate results. However, this method of testing is expensive, is a one-time event (meaning you don’t get any long-term data to tell you about your indoor environment), and requires coordination with multiple people (e.g., laboratory specialists) to get your results. 

The second option is monitoring, which tracks overall VOC concentrations in your air on a continuous basis via TVOC. In addition to being more cost-effective than lab testing, the largest benefit of monitoring is the abundance of data it provides. 

Instead of providing a single snapshot, monitors deliver continuous data that allows you to closely track TVOC levels over time, making it easy to spot patterns, find underlying causes of VOC issues, and make ongoing improvements to keep VOCs to a minimum in your building or space.

The downside of monitoring is that, by using the TVOC metric, you don’t get measurements for individual VOCs. Instead, the monitor provides a general estimate of all VOCs in the air.

Monitoring TVOC Continuously with Air Quality Monitors

What Is TVOC?

Total volatile organic compounds, or TVOC, is a measurement that tells you the overall amount of VOCs in a given space. This metric was created because it’s impossible for air quality monitors to measure every single VOC in a given space, due to the abundance of compounds as well as the wide variety of materials that emit them. Instead, TVOC acts as a pooled measurement of multiple VOCs to represent the entire group of pollutants.

Determining the exact VOCs that contribute to the overall TVOC reading has been a source of controversy in the industry, resulting in several different standards with different definitions of TVOC. To learn more about the challenges of creating a standardized definition of TVOC, check out this article for a deep dive into the technical complexities of the TVOC metric.

At Kaiterra, we use the definition provided in Mølhave et al., which describes the “Typical IAQ Mix” of 22 VOCs at concentrations similar to those determined on average in residential indoor environments.

This mix of VOCs provides a highly accurate representation of the standard indoor environment. Read this article to learn more about how TVOC sensors work and why it’s crucial to have a pre-determined list of compounds to compare sensor readings against.

By using the “Typical IAQ Mix” of VOCs, we not only get a very reliable picture of indoor VOC concentrations but can also consistently and accurately translate the measured TVOC level into meaningful insights about how the space is affecting occupants’ health and safety.

What Are Safe Levels of TVOC?

Once you’ve started collecting TVOC measurements, you’ll need a way to interpret the data and understand whether the measured levels indicate a problem. There are no federally enforced limits for VOCs in non-industrial settings in the U.S., so we instead rely on healthy building certifications like WELL v2 and RESET Air to define ideal indoor TVOC levels.

In most guidelines, a concentration of less than 500 µg/m³ is deemed acceptable, along with a stipulation that no individual VOC should exceed 250 µg/m³. While the ideal threshold varies between different guidelines, the 500 µg/m³ benchmark is consistent across third-party standards and is generally a good starting point.

How to Convert TVOC Readings From µg/m³ to ppb

While several standards use µg/m³ as their primary unit of measurement, many continuous monitors (like Kaiterra’s) provide TVOC readings as a ppb measurement, which must first be converted to µg/m³ before comparing against these standards.

Converting a TVOC reading from ppb to µg/m³ requires a conversion factor, a number that you multiply with the ppb reading to get the comparable µg/m³ measurement. The conversion factor we use at Kaiterra is 4.57 µg/m³ for every 1 ppb of TVOC. This is based on the mean molar mass of the 22 VOCs in the “Typical IAQ Mix” that we measure to get our TVOC reading.

How to Use TVOC Data

With continuous, real-time air quality data, you can track patterns in your TVOC readings and uncover sources of VOCs throughout your built environment. These sources not only include high-VOC objects and materials like furniture, carpet, or paint, but also occupant behaviors like lighting candles, spraying air fresheners, or putting on fragrances. 

Once you have analyzed the data and identified the culprit, the rest is straightforward. Determine the best course of action to reduce or remove the VOC source, and continue evaluating data from your continuous TVOC sensors to see whether or not your solution was successful.

For example, if you find that TVOC increases sharply during office cleaning hours, you could adjust your HVAC system to increase ventilation during cleaning hours and/or work with your facilities team to switch to low-VOC cleaning products. After that, you would continue monitoring TVOC levels to see if these changes sufficiently lowered VOCs or if further optimizations are needed.

The bottom line is that continuous data is a must-have if you want to effectively remove and prevent VOCs in your space. As always, choosing the right air quality monitoring solution is key to getting this level of insight out of your TVOC data.

At Kaiterra, we offer a portfolio of wired and wireless enterprise monitoring solutions, backed by comprehensive real-time analytics and industry-leading expertise, to help our customers get the most out of their data and create the healthiest spaces possible.

If you want to learn more about monitoring volatile organic compounds and how Kaiterra can help you achieve a healthier indoor environment, reach out to a member of our team today!