VOCs and Indoor Air Quality: What Off-Gassing Actually Means
You paint a room, move in new furniture, or install new carpet — and for days or weeks afterward the air smells different. That smell is VOCs: volatile organic compounds releasing from the materials into the air you breathe. Understanding what these are, where they come from, and what actually reduces them helps you prioritise the changes worth making.
The short answer
VOCs are a large family of carbon-based chemicals that evaporate at room temperature. They are found in paints, varnishes, adhesives, MDF and particleboard furniture, new carpets, vinyl flooring, air fresheners, cleaning products, and personal care items. Indoor air routinely contains higher VOC concentrations than outdoor air. The most health-relevant are formaldehyde (a known carcinogen present in most flat-pack furniture), benzene (from combustion sources and some solvents), and a range of others at lower concern levels. Ventilation dilutes concentrations most effectively. Low-VOC paints and CARB-certified furniture significantly reduce source emissions at purchase.
What VOCs are
VOC stands for volatile organic compound — "volatile" meaning it evaporates readily at room temperature, "organic" meaning it contains carbon. This is a very broad category that includes thousands of different chemicals with widely varying toxicity profiles. Some VOCs, like limonene from citrus peels, are low concern. Others, like formaldehyde and benzene, are established carcinogens. The term covers everything on this spectrum.
When people talk about off-gassing from furniture or paint, they are describing the process of VOCs evaporating from a solid or liquid material into the air. All paints, adhesives, and many synthetic materials off-gas to some degree. The question is which chemicals at what concentrations.
Main indoor sources
Paint and coatings
Traditional oil-based paints are high-VOC — toluene, xylene, and mineral spirits are typical solvents. Water-based (latex) paints have lower VOC content but are not zero. "Low-VOC" paints contain less than 50g/L VOC content; "zero-VOC" or "no-VOC" paints typically contain less than 5g/L. The odour distinction is significant: a freshly painted room with zero-VOC paint has dramatically lower off-gassing than one painted with conventional paint. VOC emissions from paint drop sharply in the first 72 hours and continue declining over weeks.
Engineered wood furniture (MDF, particleboard, plywood)
This is the most persistent and often overlooked source. MDF and particleboard are made by bonding wood particles with urea-formaldehyde (UF) or melamine-formaldehyde (MF) resins. Formaldehyde is an IARC Group 1 carcinogen — meaning there is sufficient evidence it causes cancer in humans (primarily nasopharyngeal cancer and leukaemia at occupational exposure levels). In homes, the exposure is far lower than occupational, but long-duration low-level exposure from furniture is a real source.
Unlike paint, which off-gasses quickly, UF resin in furniture continues releasing formaldehyde for months to years. The rate is highest in warm, humid conditions. A new flat-pack wardrobe in a bedroom can measurably elevate formaldehyde concentrations in that room for 12+ months.
Certification: CARB Phase 2 (California Air Resources Board) sets limits for formaldehyde emissions from composite wood products. E1 (European standard) and E0 (stricter) are equivalent standards. Look for these on furniture labels. IKEA has committed to CARB Phase 2 compliance across its range. See Formaldehyde in Furniture for full detail.
New carpets and vinyl flooring
New synthetic carpet off-gasses 4-PC (4-phenylcyclohexene), styrene, and other compounds for days to weeks after installation. The new carpet smell dissipates relatively quickly with ventilation. Vinyl (PVC) flooring off-gasses plasticisers including phthalates, particularly in warm rooms, and this continues over the life of the floor rather than just initially. Natural flooring alternatives — hardwood, cork, natural fibre rugs — have significantly lower off-gassing profiles.
Cleaning products and air fresheners
Spray cleaning products release VOCs directly into breathing air during and after use. Many contain glycol ethers, synthetic fragrances (which are complex mixtures of undisclosed VOCs), and aerosol propellants. Air fresheners — sprays, plug-ins, scented candles — are concentrated VOC sources by design. The fragrance chemicals used include acetaldehyde, benzene derivatives, and formaldehyde-releasing preservatives. Switching to fragrance-free or naturally scented alternatives reduces this source meaningfully. See What's Actually in Your Cleaning Products.
What actually reduces indoor VOC levels
1. Ventilation — most effective, free
Opening windows creates air exchange that replaces VOC-laden indoor air with outdoor air. This is the single most effective intervention for indoor VOC levels. The ideal is cross-ventilation — windows on opposite sides of a space open simultaneously to create airflow. Even 10–15 minutes of ventilation per day measurably reduces average VOC concentrations in enclosed rooms. It is especially important for the first weeks after painting, installing new flooring, or bringing in new furniture.
2. Source reduction — most durable
Choosing low-VOC paint, CARB Phase 2 certified furniture, natural fibre flooring, and fragrance-free cleaning products eliminates VOC sources rather than managing them after the fact. This is the highest-leverage action at the point of purchase.
3. Air purifiers with activated carbon — partial help for gases
HEPA filters capture particles but do not capture VOCs (gases pass through fibre filters). Activated carbon in an air purifier adsorbs some VOC molecules — but has limited capacity and is most effective at lower concentrations. An activated carbon filter helps in a room where ventilation is difficult; it is not a substitute for ventilation or source reduction. See Air Purifiers and Indoor Air Quality.
4. Off-gassing new items before use
New furniture, mattresses, and rugs emit most heavily in the first weeks. If you can, leave new flat-pack furniture assembled in a well-ventilated space (garage, balcony) for several days before moving it into a bedroom. This reduces the peak indoor emission load.
What about houseplants?
The popular claim that houseplants remove VOCs from indoor air comes from a 1989 NASA study conducted in tightly sealed chambers — not real living conditions. Subsequent research in realistic indoor settings found that the number of plants required to meaningfully reduce VOC concentrations in a room would be on the order of hundreds per square metre. Houseplants do not make a measurable difference to indoor VOC levels in practice. They improve mood and aesthetics; they are not an air quality strategy.