TVOC

TVOC, or total volatile organic compounds, is a broad metric used to express the combined concentration of a range of organic chemicals found in the air. It is not a single substance, but an aggregate indicator of indoor air quality and ventilation performance. Because the toxicity and odor of VOCs vary widely, TVOC readings should be interpreted with an understanding of the sampling method and the calibration used.

Measurement and interpretation of TVOC can be performed with real-time sensors, such as photoionization detectors (PID), which respond to a broad spectrum of VOCs, or with air samples analyzed in a laboratory using gas chromatography–mass spectrometry (GC-MS) to identify individual compounds. TVOC is commonly reported in units such as milligrams per cubic meter (mg/m3) or parts per billion (ppb), often with calibration to a reference substance like toluene. The lack of a universal standard for calibration and response means TVOC values can vary between devices and methods, limiting direct comparability.

Common sources of VOCs in buildings include interior finishing materials, paints and solvents, adhesives, cleaning products, new furniture, office equipment, cosmetics, and tobacco smoke. Outdoor air and cooking can also contribute. Ventilation rate, temperature, and humidity influence TVOC levels, as do activities such as cleaning or painting.

Health effects associated with VOC exposure range from eye and throat irritation and headaches to more serious outcomes with prolonged exposure, depending on the specific compounds present and their concentrations. TVOC is used by building managers and IAQ professionals to assess air quality and guide mitigation, such as selecting low-emitting materials or increasing ventilation. While useful, TVOC has limitations as a metric due to its broad nature and variability in chemical composition and sensor response.