Off-gassing, also known as outgassing, is the release of chemicals from materials into the air or environment. This occurs when products or materials emit volatile organic compounds (VOCs) and other airborne pollutants as they break down or degrade over time. Off-gassing can be a concern for indoor air quality and human health if the emissions contain harmful or irritating chemicals.

What Causes Off-Gassing?

There are several causes of off-gassing:

Manufacturing Processes

Many products off-gas chemicals that are used or created during manufacturing or production. Examples include:

• Plastics and resins release VOCs and plasticizers used to make them flexible and durable.
• Furniture made with glues and adhesives off-gas formaldehyde and other bonding agents.
• Permanent press fabrics release formaldehyde used for wrinkle-resistant treatment.
• Building materials like plywood, particle board, and paint off-gas formaldehyde and VOCs from binders, resins, and solvents.

During production, not all of these chemicals get locked into the final product, so leftovers continue escaping into the air slowly over time.

Inherent Chemical Makeup

Some materials are inherently prone to off-gassing due to their chemical makeup:

• Natural rubber products off-gas terpenes and other hydrocarbons inherent in rubber.
• Printed materials release VOCs from inks, dyes, and pigments, especially when new.
• VOCs inherent in crude oil are released from petroleum-based products like vinyl, synthetic fragrances, and some fabrics.

Even without added chemicals, these materials emit VOCs that are part of their basic composition.

Breakdown Over Time

As products age and break down through regular use, aging, exposure to heat/light, or microbiological decay, they release chemicals previously locked in:

• The foam cushioning in older furniture releases leftover flame retardants and plasticizers.
• Deteriorating silicone caulking and glues emit unreacted VOCs over time.
• Microbial action on materials releases VOC breakdown products like formaldehyde.

Off-gassing increases as materials degrade slowly.

Examples of Products That Off-Gas

Many common products used indoors have the potential to off-gas:

• Furniture: Particleboard, plywood, furniture finishes.
• Flooring: Carpets, laminate flooring, vinyl flooring.
• Paints, stains, and varnishes.
• Permanent press clothing and bedding.
• Plastics and rubber: Shower curtains, plastic containers, vinyl toys.
• Personal care products: Fragrances, hairspray, nail polish.
• Cleaning supplies: Solvents, air fresheners, polishes.
• Office supplies: Photocopiers, markers, glues.
• Building materials: Insulation, caulking, pressed wood, drywall.

The highest offenders are generally new products made with adhesives, solvents, and petroleum-based ingredients. But many other common materials also have the potential to off-gas.

Health Concerns of Off-Gassing

Exposure to off-gassed chemicals can cause health issues for sensitive individuals, especially at high concentrations:

Respiratory Irritation

Inhaling VOCs can irritate the eyes, nose, throat, and lungs. This can worsen asthma and respiratory conditions. Formaldehyde is a major irritant.

Headaches and Nausea

The smell of VOCs can trigger headaches, nausea, dizziness, fatigue, and flu-like symptoms in those sensitive to off-gassing.

Allergic Reactions

VOCs like formaldehyde, toluene, and benzene are common triggers for allergic reactions and difficulty breathing in those with chemical sensitivities.

Kidney and Liver Damage

VOCs like chloroform, methylene chloride, and Freons are associated with kidney and liver toxicity with long-term exposure.

Cancer Risk

Formaldehyde and benzene are classified as known human carcinogens linked to leukemia and other cancers. Other VOCs are possible carcinogens.

Children, pregnant women, the elderly, and those with asthma, allergies, or chemical sensitivities are most vulnerable to off-gassing effects.

Tips for Reducing Off-Gassing Exposure

There are several options for lowering exposure to off-gassing in homes and workplaces:

Ventilate Properly

Open windows regularly and use exhaust fans to ventilate rooms. This removes VOCs before they accumulate.

Choose Low-VOC Products

Buy paints, finishes, furniture, flooring, and building supplies with low- or no-VOC formulations.

Seal Products

Use seals like acrylic varnish on installed wood, laminate, and vinyl to prevent off-gassing. Unsealed edges have the highest emissions.

Accelerate Off-Gassing

Before installing items, air out new products in ventilated areas to accelerate release of initial VOCs.

Use Air Purifiers

Specialized air purifiers with activated carbon filters adsorb VOCs and other gases from the air.

Test Air Quality

Check indoor air quality with home test kits for VOC, formaldehyde, and carbon dioxide levels.

Buy Solid Wood

Choose solid sustainably-sourced wood over pressed/composite wood products when possible to avoid binder glues.

Off-Gassing Standards and Certifications

Several standards and certifications identify products made to minimize off-gassing:

• Greenguard Certified – Low VOC emissions during product usage.
• Greenguard Gold – Stricter criteria for sensitive environments like schools.
• GREENGUARD Children & Schools Certification – Minimal emissions for child safety.
• UL GREENGUARD Certification – Indicator of low VOC/formaldehyde emissions.
• FloorScore – Tests and certifies flooring and adhesives for indoor air quality.
• Eco-INSTITUT – European label for low emission flooring.
• OEKO-TEX Standard 100 – Test criteria for low emission textiles.
• CARB Compliant – Passes California off-gassing regulations for building materials.

Choosing products certified under these standards can help identify items less likely to off-gas. Checking for low- or no-VOC product formulations is also recommended.

Off-Gassing from Composite Wood Products

Composite wood products made with adhesives are a major concern for off-gassing emissions:

• Particleboard – Wood fragments bonded with adhesives.
• Medium Density Fiberboard (MDF) – Wood fibers and resin glues.
• Plywood – Layers of wood veneer with adhesive.
• Oriented Strand Board (OSB) – Rods of wood with resin binders.

These pressed wood products contain urea-formaldehyde (UF) resins that continuously release formaldehyde over time, especially when new. Other binders and VOCs are also emitted.

Health Effects

Formaldehyde is irritating to the eyes and respiratory system. High exposure is associated with asthma, allergies, and certain cancers. Those sensitive to chemicals can experience symptoms like headaches, dizziness, and nausea.

Regulations

California has set limits on allowable formaldehyde emissions from composite wood through CARB Airborne Toxic Control Measures. Similar regulations have been adopted nationally through the EPA.

Reducing Exposure

• Choose composite wood certified as low-emission CARB Phase 2 or EPA TSCA Title VI compliant.
• Select solid wood or alternative materials when possible.
• Seal surfaces with coats of polyurethane or primer paints.
• Accelerate off-gassing before installation by airing out in ventilated space.

Proper finished goods testing and manufacturing techniques can help reduce formaldehyde off-gassing from composite wood products.

Off-Gassing from New Furniture

New residential furniture is a major source of off-gassing in homes. Bought furniture can release VOCs for months or years after manufacturing.

Main Off-Gassing Sources

• Particleboard, MDF, plywood, OSB – Composite woods release formaldehyde.
• Glues and adhesives – Contain VOCs.
• Stains and finishes – Release solvent VOCs.
• Fire retardants – Polybrominated diphenyl ethers (PBDEs) mandated for upholstered furniture.
• Padding and stuffing – Polyurethane foam emits leftover VOCs.

Upholstered furniture has the highest emissions from embedded materials. PBDE flame retardants are particularly concerning, as they are semi-volatile and toxic.

Reducing Exposure

• Choose solid wood furniture with low-VOC stains/finishes.
• Opt for naturally less flammable materials like polyester batting.
• Purchase furnishings tested/certified for low emissions.
• Unbox and air out new furniture before installing indoors.
• Hand wash and air out new fabric coverings outdoors.
• Add new furniture slowly, rather than furnishing an entire room at once.

Proper off-gassing can help new furniture reach indoor air quality equilibrium faster before use.

Off-Gassing from Mattresses

Like furniture, new mattresses release an array of VOC emissions indoors:

Main Off-Gassing Sources

• Polyurethane foam – Emits unreacted isocyanates and VOCs.
• Adhesives – Used in multi-layer mattresses.
• Fire retardants – Added to meet flammability standards, especially in foam.
• Textiles – Fabrics, dyes, stain repellents, etc.

Since mattresses contain embedded materials, they can off-gas for extended periods after production.

Health Concerns

Isocyanate exposure can irritate eyes, skin, and lungs, potentially causing asthma-like symptoms. Other VOCs may cause nausea, headache, or dizziness in those sensitive.

Reducing Exposure

• Choose mattresses with wool, cotton, latex, or other naturally low-VOC materials.
• Look for options with GREENGUARD or other low-emission certifications.
• Remove plastic coverings and air out in open space before use.
• Add washable mattress coverings to provide barrier to emissions.
• Allow adequate off-gassing time, ideally a few weeks if possible.

Letting new mattresses properly ventilate before use can help minimize indoor VOC exposure.

Off-Gassing from Home Construction Materials

In newly constructed or renovated homes, a wide array of building materials off-gas into indoor air:

Main Off-Gassing Sources

• Composite wood products – Formaldehyde emissions.
• Insulation foam – Can contain CFCs and formaldehyde.
• VOC-containing adhesives – Glues, caulking, sealants.
• Paints and coatings – Solvent VOCs.
• PVC materials – Leach plasticizers and solvents.
• Carpeting and flooring – Adhesives and dyes contain VOCs.

Off-gassing is highest when these materials are newly installed. Emissions decrease over 1-2 years but may never fully dissipate.

Health Concerns

Exposure to high levels of VOCs may cause eye, nose, and throat irritation along with headaches or nausea in sensitive individuals. Carcinogenic VOCs are also a concern.

Reducing Exposure

• Substitute solid wood, metal, or brick alternatives when possible.
• Choose low-VOC paints, stains, caulking, insulation, and flooring.
• Ventilate home extensively after construction using fans and open windows.
• Consider air quality testing to identify primary VOC sources.
• Purify air with HEPA/carbon filtration systems.

Allowing ample ventilation time after construction helps new homes reach better indoor air quality.

Off-Gassing from Vehicle Interiors

The interiors of new cars, trucks, and other vehicles can release high levels of VOCs and other chemicals into the enclosed cabin space.

Main Off-Gassing Sources

• Plastics – VOCs from PVC, polyurethanes, vinyl, and other plastics.
• Adhesives and sealants – Used in interior parts and fittings.
• Fabrics and leather – Dyes, tanning chemicals, stain repellents.
• Flame retardants – Added to textiles and polymers.
• Residual solvents – From cleaners, lubricants, coatings.

Vehicle interiors can emit VOCs for months after manufacturing. Factors like temperature and sunlight accelerate release.

Health Concerns

Prolonged exposure to high VOC levels in vehicle interiors may cause eye, nose, and throat irritation, nausea, dizziness, and headache. Carcinogenic VOCs are also potentially emitted.

Reducing Exposure

• Open windows and set ventilation to allow maximum exterior airflow.
• Consider replacing cabin air filters more frequently when new.
• Use deodorizing charcoal bags to help adsorb VOCs.
• Allow time for off-gassing with windows down in warmer temperatures.
• Optionally use upholstery cleaners/protectants to isolate chemicals.

Adequately ventilating new vehicle interiors when possible helps reduce occupant VOC exposure.

Off-Gassing Reference Values and Limits

Various exposure limits and guidelines exist for common off-gassed indoor air pollutants:

Formaldehyde

• OSHA PEL – 0.75 ppm (parts per million)
• NIOSH REL – 0.016 ppm
• WHO IAQ Guideline – 0.1 ppm

Benzene

• OSHA PEL – 1 ppm
• NIOSH REL – 0.1 ppm
• WHO IAQ Guideline – No safe level

Toluene

• OSHA PEL – 200 ppm
• WHO IAQ Guideline – 0.26 ppm

Xylenes

• OSHA PEL – 100 ppm
• WHO IAQ Guideline – 0.23 ppm

Total VOCs

• LEED v4 – Less than 500 μg/m3
• CDPH Standard Method v1.2 – Less than 500 μg/m3

These exposure limits indicate levels at which health effects may start to be observed, helping set indoor air quality targets.

Frequently Asked Questions

What materials are highest concerns for off-gassing?

New composite wood products, upholstered furniture, mattresses, carpeting, adhesives, paints, and plastics made with VOCs and solvents have the highest potential to off-gas chemicals indoors when new.

Do off-gassed VOCs remain permanently in indoor air?

No, VOCs are gradually diluted through ventilation, filtration, and adsorption onto surfaces over time. However, some semivolatile organics like flame retardants can persist longer.

Is it safe to sleep on a new mattress without airing it out?

It’s not recommended. Letting a new mattress ventilate in an open, well-ventilated space for ideally 1-2 weeks prior to use allows VOCs and odors to dissipate, improving air quality and comfort.

Can off-gassing make pets sick?

Yes, pets can be sensitive to off-gassed chemicals. New furniture, carpeting, or renovations should be aired out before allowing pet exposure. Signs of VOC toxicity include lethargy, asthma-like coughing/wheezing, and eye/skin irritation.

Do green building certifications prohibit off-gassing materials?

Not necessarily, but they set maximum limits on VOC content and emissions from products. LEED, GREENGUARD, and Living Building Challenge have criteria focused on improving indoor air quality through material selection and ventilation.

What VOC concentration is considered high for indoor air?

As a general guideline, the CDPH Standard Method v1.2 recommends total VOCs be less than 500 μg/m3 for indoor air. Higher levels warrant investigation of emission sources and implementation of mitigation methods.

Conclusion

Off-gassing of volatile chemicals into indoor air can be a concern, particularly when new products are installed without adequate ventilation. By understanding major sources, health hazards, and mitigation strategies, off-gassing exposure can be minimized. Selecting low-VOC and naturally less emissive materials whenever possible is key, along with proper airing-out of new furnishings, construction materials, and finished spaces. Targeting a high level of indoor air quality helps provide healthy, comfortable, and productive interior environments.

Definition-of-OffGas

Off-gassing, also referred to as outgassing, is the release of volatile organic compounds (VOCs) and other airborne pollutants from materials and products into the surrounding environment. Off-gassing occurs when these chemicals within solids and liquids transition into a gaseous state in the air, a process enhanced by heat, ultraviolet radiation, microbiological processes, and other factors that increase the volatility and diffusion rates of the compounds. Many man-made substances used in the manufacture of everyday items contain and slowly release trace VOCs that can accumulate in indoor spaces, raising potential health and safety concerns related to indoor air quality.

What is Off-Gassing?

Off-gassing specifically refers to the outflow and emission of gases that were previously dissolved, trapped, or inherent within a liquid or solid material. The off-gassed substances then transition into a gaseous vapor state in the atmosphere surrounding the material. This phenomenon is also referred to as evaporative emissions or fugitive emissions.

Off-gassing is accelerated by factors like heat, sunlight, exposure to oxygen, and microbiological decay, which all increase the vapor pressures and volatility of compounds within materials, causing faster breakdown and release. Ultraviolet radiation in particular degrades the molecular bonds in materials over time, allowing trapped substances to more readily escape.

Many off-gassed substances are volatile organic compounds, or VOCs, which are carbon-based chemicals that easily transition to a gaseous vapor phase at room temperature. Common indoor VOCs given off through off-gassing include formaldehyde, benzene, toluene, xylenes, chloroform, methylene chloride, and Freons, along with a wide variety of other hydrocarbon, alcohol,