Silk & Snow Off-Gassing and Smell: What the Science Actually Says

8 min read

What Is Mattress Off-Gassing?

Off-gassing is the release of volatile organic compounds (VOCs) from materials into surrounding air. In mattresses, it occurs primarily with polyurethane foam, which is the main material in most bed-in-a-box products. During manufacturing, polyurethane foam is created through a chemical reaction between polyols and isocyanates. After the mattress is compressed, sealed, and shipped, residual compounds remain trapped within the foam structure.

When the vacuum-sealed package is cut open and the mattress begins expanding, these residual compounds volatilise, meaning they convert from solid or liquid phase into gas phase and enter the room air. This is what creates the recognisable "new mattress smell."

Off-gassing is not unique to mattresses. It occurs with new furniture, carpeting, paint, vehicle interiors, and many other consumer products containing synthetic polymers. The intensity and duration depend on the foam formulation, density, and how long the mattress was sealed during transit and storage.

What Silk & Snow Mattresses Emit and Why

The specific VOCs associated with polyurethane foam mattresses include compounds from several chemical families. Research published in Chemosphere (Xu et al., 2022, PubMed 35588879) identified the following as commonly detected in memory foam mattress emissions testing:

• Acetaldehyde: A naturally occurring compound also present in many foods; classified as possibly carcinogenic at high industrial concentrations, but typical mattress emissions are far below occupational exposure limits
• Formaldehyde: Present in trace amounts in many foam products; CertiPUR-US certification requires formaldehyde content to be below 0.5 ppm at time of testing
• Toluene and Benzene: Aromatic hydrocarbons occasionally detected in uncertified foam products; CertiPUR-US-certified foams prohibit these above trace levels
• Flame retardant residues: Legacy flame retardants (PBDEs) were widely used until 2004; modern foam uses alternatives that emit fewer VOCs

Silk & Snow's foam mattresses are CertiPUR-US certified. This certification requires independent lab testing for VOC emissions and prohibits the use of ozone-depleting substances, certain heavy metals, and specific flame retardants.

Is the Smell from Silk & Snow Harmful? What Research Says

The research consensus on memory foam mattress off-gassing is that, for healthy adults in ventilated rooms, the VOC concentrations produced are not at levels associated with adverse health effects. This holds for CertiPUR-US certified products like Silk & Snow.

However, some populations may be more sensitive to off-gassing odours:

• People with chemical sensitivities (MCS): Multiple chemical sensitivity is a contested medical diagnosis characterised by non-immune-mediated reactions to low-level chemical exposures. Individuals with this condition may find foam mattress off-gassing intolerable even at concentrations that do not affect most people.
• Infants and young children: Although adult exposure data is reassuring, children spend more time in bed proportionally and have higher respiratory rates. The American Academy of Pediatrics recommends firm, flat, unupholstered sleep surfaces for infants under 12 months, which effectively sidesteps mattress off-gassing concerns for the youngest age group.
• People with asthma or respiratory conditions: Strong odours can act as irritants and trigger symptoms in some asthma patients, even if the compounds are below health-risk thresholds. Ventilating the room thoroughly before first use is particularly important for this group.

If you are in a sensitive population, the Silk & Snow Organic model, which uses GOLS-certified natural latex rather than polyurethane foam, produces substantially less off-gassing. Natural rubber latex has a distinct, mild odour of its own initially, but it does not emit the same VOC profile as synthetic polyurethane foam.

Off-Gassing Timeline by Model

These timelines assume a bedroom with at least one operable window and standard ventilation. In sealed rooms with no air movement, off-gassing can linger for 7 to 14 days and VOC concentrations will be higher than in ventilated spaces.

How to Clear the Smell Faster: 7 Proven Methods

1. Cross-ventilate the room. Open windows on opposite sides of the bedroom to create airflow across the mattress surface. A fan positioned to draw air out of the room (exhaust mode) is more effective than one blowing air in.
2. Use an activated carbon air purifier. Activated carbon (also called activated charcoal) adsorbs VOC molecules, removing them from the air rather than just filtering particulates. Standard HEPA filters do not capture most VOCs. Look for purifiers with activated carbon stages.
3. Keep room temperature elevated. Warmer air accelerates off-gassing by increasing the volatility of trapped compounds. Setting the room to 22 to 25 degrees Celsius during the first 24 hours speeds up emission so it completes faster.
4. Remove all bedding for the first 24 hours. Sheets, mattress protectors, and pillows trap off-gassing compounds against the foam surface. Leaving the mattress uncovered allows VOCs to disperse into the room air and out through ventilation.
5. Place baking soda on the mattress surface. Baking soda (sodium bicarbonate) is mildly alkaline and can adsorb some odour compounds on contact. Sprinkle generously on the surface after unboxing, leave for 4 to 6 hours, then vacuum off with an upholstery attachment.
6. Avoid the room during peak off-gassing. The first 4 to 8 hours after unboxing produce the highest VOC concentrations. If you have a choice, unbox the mattress during the day when you can leave the room ventilating, rather than immediately before bedtime.
7. Wait 48 hours before first sleep if possible. Silk & Snow permits sleeping on the mattress the first night, but if your schedule allows, waiting 48 hours gives the foam time to off-gas substantially before you spend 7 to 8 hours with your face near the surface.

CertiPUR-US and What It Means for Silk & Snow

CertiPUR-US is a certification programme for polyurethane foam that requires independent testing to verify:

• No prohibited phthalates, ozone-depleting substances, or PBDE flame retardants
• No mercury, lead, or other heavy metals above threshold levels
• Formaldehyde emissions below 0.5 parts per million (ppm)
• Total VOC emissions below 0.5 mg/m2 per hour (at a standard test chamber air change rate)
• Physical durability performance standards (does not address off-gassing after consumer purchase)

Silk & Snow's foam and hybrid models carry CertiPUR-US certification. This does not mean the mattress has no VOC emissions; it means it meets the programme's upper limits, which are set to be conservative and protective of human health under normal indoor use conditions.

The organic model carries GOTS (Global Organic Textile Standard) and GOLS (Global Organic Latex Standard) certifications for its cotton and latex components, which have separate and more restrictive chemical input requirements than CertiPUR-US.

The Low-Odour Option: Silk & Snow Organic

If mattress off-gassing is a genuine concern for your household, the Silk & Snow Organic ($1,400 Queen) is substantially different from the foam model in this respect. Natural Dunlop latex, the material used in the comfort layer, has an inherent mild rubber scent that most people find inoffensive and that dissipates within 1 to 2 days. It does not produce the chemical-sweet odour associated with polyurethane foam.

The organic model also uses GOTS-certified organic cotton in its cover, which avoids the synthetic fabric coating chemicals that contribute to off-gassing in standard mattress covers.

Alternatives for Odour-Sensitive Buyers

For Canadians who cannot tolerate any foam off-gassing, alternatives to the standard Silk & Snow foam model include:

Innerspring and hybrid mattresses with natural fibre comfort layers (wool, silk, cotton) produce far less off-gassing than all-foam models. The pocketed coil core itself has no meaningful off-gassing, and natural fibre comfort layers add minimal VOC emissions. This makes in-store pocketed coil models like the Restonic range at Mattress Miracle a strong option for households where odour sensitivity is a concern.