October 31, 2022

TVOC Monitoring in Commercial and Office Buildings

Indoor Air Quality

Volatile organic compounds (VOCs) are a diverse group of airborne pollutants, many of which have the potential to cause short- and long-term health effects. Offices and commercial buildings are often home to a wide range of VOC-emitting products that negatively impact indoor air quality. Since many people spend a significant part of their waking hours in the workplace, reducing VOC presence is critical to maintaining a safe, comfortable work environment. 

Tracking and interpreting VOC concentrations can be complicated, so we created this guide to break down the answers to your most pressing questions, including:

  • What are volatile organic compounds and TVOC?
  • Where do VOCs come from in office buildings?
  • How is indoor TVOC measured?
  • What are safe levels of TVOC?
  • How can indoor air quality monitors help you lower TVOC levels?

What are volatile organic compounds (VOCs)?

Volatile organic compounds are a group of carbon-based chemicals that evaporate quickly at room temperature. They number in the thousands and come from both natural and human-made sources. Environmental effects of VOCs can include smog formation and reduced outdoor air quality. Indoors, VOCs can become trapped and quickly accumulate to unsafe levels. 

VOCs are often emitted from everyday products, such as building materials, cleaning chemicals, furniture, textiles, and pesticides. Many VOCs are colorless and odorless. Some are harmless, but others can cause short-and long-term health effects, making it important to monitor and minimize the presence of VOCs in the office and home.

Total Volatile Organic Compounds (TVOC) and Indoor Air Quality

Since so many chemicals fall into the category of VOCs, it’s not possible to monitor each one continuously. Instead, you can estimate VOC levels in the air by monitoring concentrations of a few common VOCs representing the group as a whole. This group is called total volatile organic compounds (TVOC). 

By measuring the airborne concentration of a few representative VOCs, you can get a clear picture of the overall quality of your indoor air. High TVOC concentrations signify that the VOCs in your building are accumulating more quickly than they’re being dispersed by ventilation and air filters. Many air quality monitors display VOC concentrations in terms of TVOC in the atmosphere.

Yes, this method can make things difficult if you’re trying to determine exactly which VOCs are most abundant in your building, but that’s not necessarily important if your primary concern is improving overall indoor air quality. Implementing methods to lower TVOC levels should improve air quality in your office building, no matter the exact makeup of the VOCs present.

Sources of Volatile Organic Compounds (VOCs) in Office Buildings

Volatile organic compounds can be a significant source of indoor air pollution in commercial buildings. They can come from a wide variety of natural and human-made sources. If harmful VOCs are allowed to remain in a building unchecked, they can accumulate to levels up to ten times higher than outdoor VOC levels, even in buildings with well-maintained ventilation systems.

Because VOCs are widely used as solvents in manufacturing, many products found in the office can emit VOCs and negatively impact the indoor air quality (IAQ) of the building. VOCs are also commonly used to manufacture building products, so renovations and new construction can off-gas high VOC concentrations. (The level of VOCs off-gassed by new furniture, building products, and other materials declines over time.) Because of this, newer, more modern commercial buildings often have VOC concentrations equal to or higher than older buildings.

Potential sources of VOCs in commercial and public buildings include:

  • Paints, solvents, stains, and varnishes
  • Adhesives, sealants, caulks, and coatings
  • Plywood and other construction materials
  • Wallpaper, carpeting, and vinyl flooring
  • Disinfectants and other cleaning products
  • New furniture and upholstery
  • Electronic devices, such as copiers and office printers
  • Printer ink
  • Air fresheners
  • Pesticides
  • Cosmetics products, including perfume and cologne
  • Polluted air from outdoors (vehicle emissions, industrial pollution)

There are thousands of different VOCs found in the above examples, not all of which are known to be harmful. Some VOCs of note for offices and commercial buildings are:

Formaldehyde: Formaldehyde resin is used as an adhesive in pressed wood products (plywood, particle board). Other sources of formaldehyde include insulation materials, adhesives, flame-resistant fabrics, carpets, and cigarette smoke. Formaldehyde is classified as a probable human carcinogen and can also cause watery eyes, coughing and wheezing, nausea, skin irritation, and burning in the eyes, nose, and throat. 

Benzene: Benzene is commonly found in glues, paints, furniture wax, vehicle exhaust, and tobacco smoke. One of the top 20 chemicals in the U.S. for production volume, benzene is also a known carcinogen. Potential effects include harm to bone marrow, decreased red blood cell count, anemia, impaired immune system, excessive bleeding, and leukemia. 

Methylene chloride: Sources of methylene chloride include dry cleaning chemicals, paint removers, degreasers, and some cleaning products. Exposure to methylene chloride has been linked to harmful effects on the eyes, skin, heart, and liver. It can also cause dizziness, drowsiness, nausea, numbness, and tingling limbs.

Styrene: Commonly used in the manufacture of resins, rubber, and plastic, styrene can come from packaging, appliances, building materials, vehicle exhaust, and tobacco smoke. Exposure to styrene may cause dizziness, headache, fatigue, difficulty concentrating, and central nervous system damage. 

Toluene: Toluene is used to manufacture many dyes, paints, adhesives, solvents, and fingernail polish. It’s also found in gasoline and vehicle emissions. Toluene exposure is associated with eye and nose irritation, confusion, dizziness, tiredness, muscle fatigue, skin reactions, and kidney and liver damage.

Other common VOCs found in commercial buildings include tetrachloroethylene, ethanol, acetone, d-Limonene, and chloroform.

How can you measure TVOC levels?

Because there are so many different VOCs, it isn’t possible to monitor them all. Instead, the best way to get an idea of the overall VOC levels in your building is to use indoor air quality monitors to track concentrations of a representative group of VOCs and extrapolate the data to calculate indoor TVOC levels. Using TVOC levels to measure air quality simplifies the reporting process, making it easier to detect and respond to any air quality concerns.

TVOC Measurement Units: How Are VOCs Measured?

First, it’s important to understand how to interpret TVOC level readings. If you use an IAQ monitor, it will display TVOC levels using one of the following VOC units of measure:

  • Parts per million (ppm)
  • Parts per billion (ppb)
  • Milligrams per cubic meter (mg/m3)
  • Micrograms per cubic meter (µg/m3)

All of these VOC measurement units are used to describe the concentration of VOCs found in the air. Mg/m3 and µg/m3 indicate the ratio of the mass of VOCs per cubic meter of air. Ppb and ppm concentrations are calculated using atmospheric pressure, temperature, and TVOC molecular weight to convert the unit from mg/m3 or µg/m3.

To convert TVOC from mg/m3 to ppm, use the following equation: 24.45 x concentration (mg/m³) ÷ molecular weight.

To convert TVOC from ppm to mg/m3, use 0.0409 x concentration (ppm) x molecular weight.

To convert ppb to ppm, divide the number by 1,000. (So, taking VOC levels from ppb to mg/m3 would mean dividing the reading by 1,000 to convert the VOC ppb to ppm, then using the above equation to convert ppm to mg/m3.)

You can use whichever VOC molecular weight you desire for calculating TVOC levels. For example, Atmocube uses the average molecular weight of 100 g/mol. The RESET building standards use isobutylene as the reference at 56.1 g/mol.

TVOC Measurement Methods: How Air Quality Monitors Detect VOCs

There’s more than one way to calculate TVOC levels in the air, which is something to consider when choosing a VOC monitoring system.

Some VOC meters use a process called photoionization (PID), which uses a UV light to charge VOC molecules and create an electric current. By monitoring the strength of the current, the meter can calculate the concentration of VOCs in the air. PID monitors are often used for on-site air quality testing.

Another type of VOC monitor technology is flame ionization (FID). This process is similar to PID, but it uses a hydrogen flame instead of a UV light to charge VOC molecules in the air. The charged ions are measured by the monitor and used to calculate TVOC levels. 

Metal oxidation (MOx) detectors are the preferred IAQ technology for continuous air quality monitoring. They use a heated film of MOx nanoparticles to react with VOCs in the air. As the metal surface comes into contact with different VOCs, its electrical resistance changes. Those changes are then measured to calculate TVOC concentrations. MOx sensors are very sensitive to changes in gas composition, making them a reliable option for tracking TVOC over time and detecting data trends.

Safe Levels of TVOC in Office Buildings

Once you start monitoring TVOC in your building, the next step is to compare your data with different TVOC standards to determine whether the measured levels pose an air quality risk to the building’s occupants. These aren’t legal guidelines, but VOC levels charts from the following organizations can be a helpful tool in maintaining the air quality in your office or commercial building.

Note: There is no uniform standard for calculating VOC emissions using TVOC. Some standards list the specific VOCs used in their calculations, while others may not. To determine the potential harm of VOCs in your building, you’ll need to use a monitor that detects dangerous VOCs, such as formaldehyde.

World Health Organization (WHO) TVOC Standards

The European indoor air quality guidelines released by the WHO recommend a target level under 0.05 ppm or 0.25 mg/m3. VOC ppm from 0.20 to 0.61 is only okay for temporary exposure, and anything over 0.61 ppm is considered a dangerous TVOC level.

RESET Indoor Air Quality Standards for TVOC

Acceptable indoor VOC levels (in ppm) include anything under 0.25 ppm, or 500 µg/m3. For a building to be considered “high performance,” TVOC levels shouldn’t exceed 0.20 ppm or 400 µg/m3.

LEED Green Building Rating System

Indoor TVOC levels should be capped at 0.25 ppm, or 500 µg/m3.

OSHA Safe Building Standards

While OSHA doesn’t have specific guidelines for TVOC in the workplace, they do publish standards for exposure to some specific VOCs, such as formaldehyde. (Levels shouldn’t exceed 0.75 ppm, though OSHA notes that any exposure to formaldehyde concentrations over 0.10 ppm can cause respiratory irritation.)

Health Effects of VOC Exposure

VOCs include a diverse group of organic chemicals. Some have no known effects on human health, while others are highly toxic. Common health effects associated with VOC exposure include headaches, nausea, loss of coordination, and eye, nose, and throat irritation. Some VOCs have been linked to kidney, liver, and central nervous system damage. Others — such as benzene and formaldehyde — are known or suspected carcinogens.

Signs of VOC exposure include skin rashes, itchy or watery eyes, headache, fatigue, dizziness, trouble breathing, nausea, vomiting, nosebleeds, and nose and throat irritation. Sometimes, this group of symptoms is called sick building syndrome (SBS), also called building-related illness (BRI). SBS refers to situations where building occupants experience discomfort and health symptoms that seem linked to time spent in a specific building but don’t have any apparent cause.

SBS is difficult to diagnose, as symptoms differ for everyone, but it’s directly linked to poor indoor air quality. The EPA lists poor ventilation, high TVOC levels, and biological contaminants as causes or contributing factors to SBS.

The Importance of Continuous TVOC Monitoring

By installing an air quality monitor in your building, you can monitor volatile organic compounds (VOCs) concentrations in real-time. Then, you can compare the readings to the above clean air standards to see if you need to take action. Tracking TVOC levels also gives you the data to determine trends in your building’s IAQ and even spot potential sources of VOC contamination.

Atmocube's Dashboard: the TVOC readings

For example, you can note if (and how much) renovations, cleaning procedures, or other office activities affect the air quality in your building. Then, to decrease the impact of VOCs on office air quality, you can integrate your IAQ monitor to your building management system (BMS). When the monitor detects an air quality problem, it can trigger the BMS to increase ventilation or air conditioning. If you don’t have a BMS, the building manager or landlord can monitor and respond to IAQ alerts.

Choosing a Commercial Air Quality Monitor for TVOC Measurements

There are two different types of air quality monitors that measure TVOC. Portable, consumer-grade models are typically fairly small and affordable (like Atmotube PRO). Professional-grade monitors can be portable or stationary (like Atmocube). These are more useful for continuous monitoring of an entire building and can be used to help you comply with WELL, RESET, Fitwel, LEED, and other green building standards. 

TVOC Monitoring in Office Buildings: A Summary

A building’s indoor air quality can significantly impact occupants’ comfort, health, and productivity. VOCs have been linked to a wide range of health effects, and it’s important to minimize their presence in office and commercial buildings. Air quality monitors that continuously measure TVOC concentrations can help building managers and owners respond quickly to measurements that exceed safe building standards. Reducing indoor VOCs is integral to maintaining good indoor air quality in any building.

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