Why monitor indoor TVOC levels?
Volatile organic compounds (VOCs) are organic chemicals that evaporate easily at room temperature, releasing gases into the environment. They are commonly emitted from everyday products and materials such as paints, varnishes, furniture, carpets, adhesives, cleaning products, air fresheners, and building materials. Common examples of VOCs include benzene, toluene, xylene, formaldehyde, methylene chloride, and ethylene glycol. VOCs are also released by humans and animals through breath, sweat, and directly from the skin.
Total VOC (TVOC) refers to the total concentration of multiple VOCs that are simultaneously present in the air. Because many different VOCs can be present at the same time, measuring each compound separately is difficult. TVOC provides a practical, overall indicator of indoor air quality.
Why measure TVOC?
VOCs are always present, both indoors and outdoors. However, indoor concentrations are typically 2–5 times higher — and in some cases even up to 1000 times higher — depending on activities and materials in the space.
Different rooms also have different VOC profiles; for example cleaning products in kitchens and bathrooms, furniture and carpets in living spaces, or fuels and chemicals in garages.
Exposure to high VOC levels can affect health. Short-term exposure may cause headaches, eye and throat irritation, dizziness, or allergic reactions. Long-term exposure — especially at high concentrations — may damage the liver, kidneys, or nervous system, and some VOCs are known carcinogens.
New buildings, particularly those less than two years old, often have the highest VOC levels due to off-gassing from construction materials and finishes.
In addition, hospitals and nursing homes are especially prone to high VOC levels due to frequent use of disinfectants and cleaning agents.
TVOC monitoring and smart ventilation
Modern ventilation systems use TVOC sensors to track real time air quality. For precise monitoring, Sentera TVOC sensors measure TVOC concentration, temperature, and relative humidity, with high selectivity for H2. In indoor environments, H2 levels correlate with carbon dioxide (CO2) because human breath contains significant amounts of both — approximately 4% CO2 and 10 ppm H2. By detecting both gases, ventilation systems can distinguish human presence from other pollutant sources and adjust airflow accordingly.
This demand-controlled ventilation is especially useful in spaces where indoor air quality needs continuous optimisation, such as living rooms, offices, and industrial environments.
When VOC levels reach critical thresholds, sensors can alert users via LED, SMS, or email, signalling that ventilation should be increased.
With this approach, ventilation systems can:
- Detect occupancy levels
- Differentiate between human-sourced and material-sourced pollutants
- Optimise ventilation based on actual air quality needs
This ensures healthy indoor air, enhanced comfort, and energy-efficient ventilation.