Mattress Off-Gassing: How Long It Lasts & How to Stop It

New mattresses made from synthetic materials (polyurethane memory foam, polyester) off-gas chemicals called VOCs for between 48 hours and a few weeks.

The new mattress smell can put you off using your bed for the first few nights, and can be unsafe for babies and young children.

But there are ways to speed up off-gassing or avoid it altogether.

What Is Mattress Off-Gassing?

Mattress off-gassing is the release of volatile organic compounds (VOCs) from a new mattress into the surrounding air.

What Causes Mattress Off-Gassing?

Mattress off-gassing is caused by VOCs escaping from the synthetic materials inside a new mattress (polyurethane foam, adhesives, and synthetic cover fabrics).

• Polyurethane foam can release solvents such as toluene and acetone.
• Adhesives that bond mattress layers together can release formaldehyde, one of the six most common toxic chemicals in mattresses.
• Synthetic cover fabrics such as polyester can release amides, including formamide (Kim et al., 2015).

A mattress made from natural materials (organic latex, cotton, and wool) contains fewer VOCs, so it gives off little or no chemical smell.

What Are VOCs and Why Are They a Concern with Mattresses?

Volatile organic compounds (VOCs) are chemicals that escape as gases from solid or liquid products.

A new mattress is one of many VOC sources in a home, alongside paints, cleaning products, and other new furniture.

Concentrations of many VOCs run up to ten times higher indoors than outdoors (EPA). The health effects of VOC exposure are covered in the toxicity section below.

The new mattress smell fades as the VOCs disperse. Some mattress types take much longer than others to finish off-gassing.

How Long Does Mattress Off-Gassing Last?

Mattress off-gassing lasts from 48 hours to a few weeks, depending on the mattress materials.

VOC release from new memory foam mattresses peaks on the first day and drops over the next two days. But memory foam still emits small amounts of VOCs a month later (Beckett et al., 2022).

The more synthetic foam a mattress contains, the longer its off-gassing lasts.

• Memory foam mattresses take the longest of any type.
• Synthetic latex mattresses take almost as long as memory foam.
• Organic latex mattresses do not require an off-gassing period according to manufacturers such as Avocado and PlushBeds, because natural latex releases far fewer VOCs.
• Innerspring mattresses finish off-gassing sooner than all-foam mattresses, because their steel coil cores don't release VOCs.
• Hybrid mattresses contain steel coils under a foam or latex comfort layer. The off-gassing period for a hybrid mattress depends on whether the comfort layer is made of memory foam or latex.

The longer the off-gassing lasts, the longer you breathe those VOCs once the mattress is in use. Researchers have measured those exposures to test whether off-gassing is toxic.

Is Mattress Off-Gassing Toxic?

Mattress off-gassing is not toxic to adults at the levels measured from new mattresses, although higher VOC exposures do cause health effects.

In lab testing of new memory foam mattresses, total VOCs in the room air averaged 20 to 33 micrograms per cubic meter over the first month, which is inside recommended indoor air limits (Beckett et al., 2022).

Whether a VOC exposure harms you depends on how much you breathe in and for how long. In larger amounts, VOCs can cause headaches, nausea, and irritation of the eyes, nose, and throat (EPA).

Babies and young children are particularly vulnerable to VOC release from polyurethane (PU) mattresses. Researchers estimated that acetaldehyde, formaldehyde, and benzene emissions from PU mattresses could reach levels of concern in the air the child breathes (Oz et al., 2019).

Sleeping on a polyurethane mattress increases how much you breathe in, because body heat speeds up VOC release from the foam.

Manufacturers of synthetic mattresses tell you to air a new mattress out for 24 to 72 hours before sleeping on it, or until the off-gassing smells fade. If you want to use your mattress sooner, you can speed up the off-gassing with the methods below.

How to Speed Up Mattress Off-Gassing

To speed up off-gassing, work through the eleven methods below. The list runs in the order you would use the methods, from unboxing day to fitting the protector.

1. Air the mattress in a well-ventilated room for at least 24 hours. Unwrap the mattress as soon as it arrives, open the windows, and point a fan across the surface to blow the VOCs out of the window.
2. Air the mattress outside in direct sunlight when the weather allows. UV light increases polymer outgassing (Khassanchine et al., 2006). A mattress's foam and synthetic cover are both polymers. Bring the mattress back inside before nightfall so it stays dry.
3. Warm the bedroom, then air it out. Heat sped up the VOC release from polyurethane mattresses more than humidity or carbon dioxide did in lab tests (Oz et al., 2019). Open the windows wide once the room is warm, and the heated air carries the VOCs out.
4. Run an air purifier with an activated carbon filter next to the mattress. The EPA advises using an activated carbon filter for removing gases such as VOCs, because a particle filter on its own does not capture gases (EPA).
5. Place bamboo charcoal bags on and around the mattress. The charcoal absorbs VOCs from the air around the mattress. Refresh the bags by leaving them in direct sunlight for two hours.
6. Sprinkle baking soda over the whole surface, leave it for at least 30 minutes, then vacuum it off. Baking soda absorbs odors without adding any chemicals of its own.
7. Vacuum the whole mattress with an upholstery attachment.
8. Walk or jump across the mattress to squeeze the trapped gases out of the foam. Jump only on an all-foam or latex mattress, because the method can damage springs. Lay the mattress flat on the floor first to protect your bed frame.
9. Keep scented candles, air fresheners, and perfumes out of the room. A synthetic fragrance covers the chemical smell, so you cannot tell when the off-gassing has finished.
10. Fit a mattress protector only after the chemical smell has gone. A protector fitted on unboxing day traps the remaining VOCs inside the mattress. Once the smell has cleared, an OEKO-TEX certified mattress protector keeps dust mites and other allergens out of the mattress.
11. Check the user manual for the manufacturer's own airing instructions. Airing times differ by brand and model, so the user manual's timing overrides any general figure.

The eleven methods above are for the mattress you already own. When buying your next mattress, you can choose one that barely off-gasses at all.

How to Avoid Off-Gassing When Buying Your Next Mattress

To avoid mattress off-gassing when buying your next mattress, choose one made from certified organic materials, or buy one that is no longer new.

#1 Buy an Organic Mattress

An organic mattress produces the least off-gassing because organic latex, organic cotton, and wool contain few or no chemicals that escape as VOCs.

An organic hybrid with organic cotton batting is also low in VOCs. Our guide to the best organic mattresses lists the certified models we have tested and recommend.

#2 Look for Independent Certifications

Independent certifications verify a brand's low-VOC claims. GREENGUARD Gold and CertiPUR-US both test products for low VOC emissions.

The two mattress certifications cover chemical safety only, so a fully synthetic mattress can hold either one.

GOTS (Global Organic Textile Standard) and GOLS (Global Organic Latex Standard) are the labels that verify organic content.

#3 Buy a Slightly Used Mattress

A slightly used mattress has already finished its off-gassing in someone else's home. Sites such as Craigslist and Facebook Marketplace list slightly used mattresses. Inspect the mattress in person before you pay.

#4 Read Owner Reviews

Owner reviews tell you which models produce a strong chemical smell and which do not. Watch for fake reviews and greenwashing in the product descriptions.

Frequently Asked Questions

Can You Return A Mattress That's Off-Gassing Excessively?

Yes, you can return a mattress that off-gasses excessively if you are within the sleep trial period. A sleep trial lets you return the mattress for any reason within a specified period, usually between 90 and 365 nights.

If your mattress did not come with a sleep trial, the return is at the retailer's discretion, so check the returns policy before you buy.

Do Air Mattresses Produce An Off-Gassing Smell?

Yes, air mattresses produce an off-gassing smell. A standard air mattress is made from PVC, a plastic that releases VOCs when new. The airing methods above work on an air mattress too.

Our guide to eco-friendly air mattresses lists low-VOC airbeds that are made from the safest materials.

Can You Off-Gas A Mattress In The Cold?

Yes, you can off-gas a mattress in the cold, but the process takes longer because VOCs escape more slowly from cold foam. Ventilation still helps at any temperature. If you can, move the mattress somewhere warmer to finish the job.

Is It Safe To Sleep On An Off-Gassing Mattress?

It is safe to sleep on an off-gassing mattress if you are a healthy adult, although you may experience side effects such as a mild headache or irritated eyes while the smell lasts.

It is not safe for babies and young children to sleep on an off-gassing mattress. Infants should only sleep on synthetic mattresses that have already off-gassed. Ideally, buy a baby or toddler mattress that is GREENGUARD Gold certified for low emissions.

The Final Word

An off-gassing mattress smells unpleasant and can cause some side effects, but it is not dangerous to healthy adults. The smell is strongest when the mattress is new, and clears faster in a well-ventilated room.

Babies and young children should not sleep on a mattress that is still off-gassing and ideally should have a mattress that is certified for low emissions.

If you want to avoid off-gassing completely, buy a certified organic mattress.