Measurements · Gases & VOCs
VOC (Total)
Also known as volatile organic compounds, TVOC, total VOC
Total volatile organic compounds: a broadband, PID-based indicator of solvent and fuel vapors.
What it is
What are VOCs?
Volatile organic compounds (VOCs) are a large family of carbon-based chemicals that evaporate readily at room temperature. Indoors they are emitted by paints and solvents, adhesives, cleaning products, air fresheners, new furniture and flooring, cooking, printers, and personal-care products; outdoors they arise from vehicle exhaust, fuel evaporation, and industrial processes. Air-quality monitoring usually reports total VOC (TVOC), a single number summing the mixed response of the sensor to whatever compounds are present, rather than identifying individual species.
TVOC is best read as an indicator of chemical load and freshness: a rising trend means something is off-gassing or a process is emitting, and calls for a closer look.
Health and operational effects
The health impact of VOCs spans a wide range because the category does. Many cause short-term irritation of the eyes, nose, and throat, headaches, and that characteristic "new building" stuffiness; some, such as benzene and formaldehyde, are established carcinogens with no safe exposure level. Because TVOC lumps benign and harmful compounds together, a high reading is a signal to investigate the source rather than a direct measure of toxicity.
Operationally, VOCs drive occupant complaints, feature in green-building and low-emission product certifications, and matter acutely in laboratories, manufacturing, cannabis and print facilities, and anywhere solvents are handled.
Limits
VOC (Total) Limit Values
The published values, by averaging period; each links to the standard that sets it.
1-hour, information-based threshold
A01 Air Quality (TVOC)
15-minute, above background
Level at the work-area perimeter
One-time test, investigate above
Acceptable
High performance
- SCAQMD 1180 730 ppb: total VOCs as non-methane hydrocarbons
- WELL v2 500 µg/m³: continuous TVOC monitoring, an alternative to laboratory testing of benzene, formaldehyde, and toluene
- NYSDEC DER-10 5 ppm: total organic vapors at the downwind perimeter; work halts until readings drop below (Appendix 1A)
- NYSDEC DER-10 25 ppm: activities shut down; no averaging period stated (Appendix 1A)
- LEED v5 500 µg/m³: compare individual VOCs with health-based limits and take corrective action
- RESET Air 500 µg/m³: below (220 ppb)
- RESET Air 400 µg/m³: below (176 ppb)
TVOC is typically reported in ppb (or as an index). Because different sensors weight compounds differently and TVOC has no single regulatory limit, interpret it as a relative trend against your own baseline: what matters is a sustained rise above the normal level for that space. The WELL Building Standard sets TVOC at 500 µg/m³ where it is monitored continuously, as an alternative to laboratory testing of benzene, formaldehyde, and toluene; where a specific harmful compound is suspected, follow up with speciated measurement rather than relying on the aggregate number.
How it is measured
How VOC (Total) Is Measured
Two families of sensor dominate. Metal-oxide (MOX) sensors are low-cost, respond to a broad range of compounds, and are ubiquitous in indoor TVOC monitors; they report relative changes well but are not compound-specific and drift over time. Photoionization detectors (PID) use ultraviolet light to ionize VOC molecules and measure the resulting current. They are more sensitive and quantitative, widely used in industrial hygiene and fence-line monitoring, and better suited where an actual concentration in ppb or ppm is required. For identifying and quantifying individual species such as benzene, a gas chromatograph is needed.
Built into Aethair IAQ1
Measured by the monitor's own sensors, calibrated before it ships: nothing to add.
Aethair PRO cartridges4
A pre-calibrated cartridge in one of Aethair PRO's sockets: Aethair VOC (ppm PID), Aethair VOC (ppb PID), Aethair MultiGas+, and more.
An instrument on Thiamis2
A third-party instrument connected to a Thiamis gateway, reporting into the same Environet account.
Placing VOC sensors
For indoor air quality, place sensors in the occupied breathing zone away from obvious point sources so the reading reflects general exposure rather than a single emitter (unless source-hunting is the goal, in which case move a portable instrument toward the suspected origin). For industrial and fence-line work, position PID instruments downwind of the process with wind data alongside so plumes can be traced.
Every device and option that measures VOC (Total) 5
| Device / option | Type | Base platform | Measures |
|---|---|---|---|
Aethair IAQ built-in sensors | Built-in sensors | Aethair IAQ | |
 Aethair VOC (ppm PID) 0d03 0d13 0d25 | Gas sensor cartridge | Aethair PRO | |
 Aethair MultiGas+ 0d16 | Gas sensor cartridge | Aethair PRO | |
 Particles Plus · Particles Plus 5301, Particles Plus 5301-AQM1, Particles Plus 5301-AQM2… | Particulate & Dust Monitors | Thiamis | |
 RAE · MultiRAE Lite, MultiRAE, MultiRAE Pro… | Gas Detectors | Thiamis |
Where it is monitored
Solutions That Monitor VOC (Total)
Each one links to the solution page showing what that industry measures it for.
Indoor Air Quality
Core parameterTotal VOCs capture the chemical load an indoor space carries from furnishings, cleaning products, print and process equipment, and new building materials.
Oil & Gas / Petrochemical
Core parameterFugitive VOC emissions are the signature air-quality concern of oil and gas operations, from wellheads and tank batteries to refineries, and they include hazardous species such as benzene.
School Air Monitoring
Core parameterTotal VOCs in schools come from cleaning products, art and science supplies, furnishings, and new building materials, and they accumulate in rooms that are not ventilated in step with their use.
Cleanrooms, Labs & Manufacturing
Often addedParticle counting and controlled environments
Healthcare Air Monitoring
Often addedClinical air quality, pressurization, and patient safety
HVAC & Building Management
Often addedMonitor ventilation and filtration, with data for your BMS
Landfill, Biogas & Odor
Often addedMethane, H₂S, and odor complaint response
Occupational Safety & Industrial Hygiene
Often addedWorker exposure, confined space, and heat stress
Outdoor Monitoring
Often addedContinuous outdoor air quality networks that sit alongside reference monitors
Perimeter Monitoring
Often addedSite boundary dust, silica, and noise compliance
Wildfire Air Monitoring
Often addedSmoke plumes, black carbon, and community exposure
Article Library
Reading on VOC (Total)
How Building Certifications Use Air Quality Monitoring
How WELL and LEED v5 incorporate air quality monitoring, why both frameworks are moving toward continuous performance, and what that means for building teams.
Workplace Air Quality Monitoring for Offices and Employers
How to monitor workplace air quality in offices, what to measure for employee health and focus, and how continuous connected monitoring documents the result.
Indoor Air Quality in Schools: Standards & Monitoring 2026
Indoor air quality in schools: which standards apply, what to monitor, and how CO2 and ventilation affect student attendance, health, and test scores.
WELL Building Standard Air Quality: CO2 & PM2.5 Limits 2026
WELL v2 air quality limits: PM2.5 at 15 µg/m³, formaldehyde at 50 µg/m³, CO2 at 900 ppm for ventilation monitoring, plus the monitoring WELL verifies.
Industrial Perimeter Air Quality Monitoring: Action Levels
What industrial perimeter monitoring requires at fenceline and construction sites: DER-10 CAMP action levels, EPA fenceline rules, and continuous records.
IAQ Monitoring Parameters: PM2.5, CO2, VOCs & Formaldehyde
Indoor air quality monitoring parameters explained: PM2.5, CO2, VOCs, and formaldehyde, plus the sensors, thresholds, and OSHA, ASHRAE 62.1, and WELL limits.
Related
More in Gases & VOCs
Questions
VOC (Total) FAQ
What is TVOC and how is it different from measuring a specific chemical?
TVOC (total VOC) is the summed sensor response to all volatile organics present, reported as one figure. It flags that chemical load is elevated but does not identify which compound. To measure a specific harmful chemical such as benzene or formaldehyde, a compound-specific method (PID with speciation, gas chromatography, or a dedicated formaldehyde sensor) is required.
What is a normal indoor TVOC level?
There is no universal limit, and readings vary by sensor type, so the meaningful comparison is against the space's own baseline. A sustained rise after new furnishings, painting, or a process change is the signal to act. The WELL Building Standard provides a reference target for certified buildings.
MOX or PID: which VOC sensor should I use?
Metal-oxide (MOX) sensors are ideal for low-cost indoor TVOC trending and alerting. Photoionization detectors (PID) are more sensitive and quantitative, and are the choice for industrial hygiene, fence-line, and any application needing an actual concentration value.
How do I monitor VOCs on my site?
Aethair IAQ includes a built-in VOC sensor for indoor TVOC monitoring, and Aethair PRO takes PID VOC cartridges. For industrial VOC, benzene/BTEX, or fence-line work, use the configurator to pair Thiamis with a PID multi-gas monitor or a portable gas chromatograph.
Monitor VOC (Total) on the Record
Schedule a callConfigure VOC (Total) Monitoring All parameters
A 30-minute call: you tell us about your application, then we demo the solution for it.