VOC stands for volatile organic compounds, a broad group of carbon-based chemicals that easily evaporate into the air at room temperature. They originate from many everyday sources such as paints, cleaning products, furniture, fuels, and cooking, and can influence indoor air quality by causing odors or irritation when levels are elevated.
The VOC sensor in Ruuvi Air helps you detect potential pollution sources and improve ventilation or product choices for a healthier indoor environment. As a broad-spectrum gas sensor, it detects a wide range of VOCs — some harmless and others potentially harmful — allowing you to monitor changes in your indoor air. The VOC index reported by Ruuvi Air shows a trend, helping you easily see when VOC levels have increased or decreased compared to previous readings.
Why Ruuvi Air doesn’t show “absolute” VOC values
VOC isn’t one gas—it’s a broad family (solvents, aromas, fuels, cleaning agents, etc.). A single low-power sensor can’t chemically identify and quantify each one separately. Ruuvi Air uses a broad-spectrum gas sensor (MOX) that reacts to the total mix of oxidizable organic compounds. It measures changes in conductivity caused by many VOCs at once, not a lab-grade concentration (ppb) for each compound.
To be able to measure accurate compound-by-compound concentrations, labs use GC-MS, a gas chromatography-mass spectrometry or similar instruments. They are bulky, very expensive, and not practical for continuous home monitoring. The VOC index is designed to be actionable at home: it tells you when VOCs rise or fall compared to your normal concentration level.
What is the Ruuvi VOC Index
The VOC index measured by the onboard Sensirion SEN66 sensor is a relative air-quality indicator that reflects current volatile organic compound levels compared to the sensor’s recent history, rather than providing an absolute concentration. It relies on a gas index algorithm with a 7-day learning baseline, where typical background air is mapped to 100; values above or below this point indicate higher or lower VOC presence, similar to how a human nose detects changes in odor. It doesn’t label every molecule, but it reliably shows when your indoor air has more or fewer VOCs than usual, helping you decide when to ventilate or adjust habits. 
The scale in Ruuvi Air ranges from 1 to 500, allowing different air conditions to be quantified on the same relative scale. Values above 100 indicate higher VOC levels than average, while values below 100 suggest cleaner air with fewer VOCs present.
For best results, monitor the index over several days and pay attention to any changes in activities or products that may influence indoor air quality.
What the VOC Index numbers tell you about your indoor air
It’s useful to remember that VOC covers a wide family of substances, and many are a normal part of everyday life. Natural aromas from cooking, coffee, spices, citrus peels, or even certain houseplants can nudge the VOC Index upward for a short time without indicating a health hazard. Light fragrances from personal care products or mild cleaners may do the same. In well-ventilated spaces, these brief increases typically settle back toward the baseline around 100 as fresh air dilutes the compounds.
The VOCs that deserve more attention are usually tied to stronger or longer-lasting sources. Fresh paints, varnishes, adhesives, and new furniture or carpets can off-gas for days or weeks; certain solvent-based cleaners and fuels, or emissions from attached garages and poorly ventilated appliances, can also sustain elevated levels. When the Index remains well above 100 for extended periods—rather than spiking and falling—it’s a sign to improve ventilation, air out new materials, or reconsider the products being used.
In practice, focus on trends rather than single moments. A quick rise during cooking followed by a return to normal is expected; a persistent elevation after introducing a new item or using a strong product suggests a source worth addressing. If you’re sensitive to odors or irritants, choosing low-VOC products and airing out activities like painting or deep cleaning can help keep your indoor air more comfortable.
Conclusion
Ruuvi Air’s VOC index makes indoor air quality easier to understand by focusing on trends rather than absolute values. When setting up the device for the first time, keep in mind that the VOC index requires a 7-day learning period to establish its baseline.
By tracking changes over time and relating them to everyday activities, you can quickly spot sources of pollution and take simple actions—such as improving ventilation or adjusting product choices—to maintain a healthier indoor environment.