What is Off-Gassing and Why Does it Happen?
Off-gassing is the process by which a new product, especially one containing synthetic materials, releases volatile organic compounds (VOCs) into the air. This is what causes that distinct "new mattress" or "new car" smell. In the context of a mattress, VOCs are byproducts of the manufacturing process, often found in foams, adhesives, and chemical flame retardants. While many mattresses are now made with CertiPUR-US® certified foams that have lower VOC emissions, the odor can still be noticeable, particularly with mattresses that are compressed and vacuum-sealed for shipment in a box. This packaging traps the gases, leading to a more concentrated odor upon unboxing.
For most people, the low levels of VOCs from a mattress are not a health risk, but they can be irritating for those with chemical sensitivities or respiratory issues like asthma. Symptoms can include headaches, dizziness, or irritation of the eyes, nose, and throat. Proper ventilation is the primary and most effective way to address off-gassing and minimize any potential discomfort.
Factors That Influence How Long a Mattress Airs Out
The time required for a mattress to completely air out is not a single, fixed period. Several key factors play a role in determining how long the process takes.
Mattress Material and Construction
- Memory Foam: Known for its strong contouring properties, memory foam tends to have the most significant off-gassing. Denser foams will off-gas for longer periods. Expect anywhere from a few days to several weeks for the odor to fully disappear.
- Hybrid: These mattresses combine a spring coil core with foam layers. The presence of springs allows for better airflow, which helps the off-gassing process move faster than an all-foam mattress. Most of the smell should dissipate within the first few days.
- Innerspring: Traditional innerspring mattresses contain very little foam, so off-gassing is minimal to non-existent. Any mild factory or packaging smell should fade within hours.
- Natural Latex: Natural latex is made from rubber trees and often off-gasses far less than synthetic foam. The odor may be slightly sweet or rubbery but is generally not as harsh. It typically airs out within a few days.
- Mattress-in-a-Box vs. Flat-Packed: Mattresses shipped in a compressed and boxed state hold onto VOCs more tightly. Releasing the vacuum seal triggers a more concentrated burst of off-gassing compared to a mattress that is shipped flat and has already had some opportunity to breathe.
Room Ventilation and Airflow
How well you ventilate the room is arguably the most important factor in speeding up the airing process. A stuffy, closed-off room will cause odors to linger, while a well-circulated space will help disperse the VOCs more quickly. Leaving windows open and using fans can significantly reduce the waiting time.
Personal Sensitivity to Odors
Individual sensitivity to smells also plays a major role. What one person considers a mild, tolerable odor, another may find overwhelming. For those who are more sensitive, the process will subjectively feel longer, even if the VOCs are at low levels.
A Step-by-Step Guide to Speeding Up the Airing Process
- Unbox Immediately: As soon as your new mattress arrives, get it out of the packaging. The off-gassing cannot begin until the mattress is exposed to air.
- Move to a Well-Ventilated Area: If possible, take the mattress to a spare room, garage, or even outdoors on a warm, sunny, non-humid day. Stand it on its side against a wall to expose both faces to fresh air.
- Maximize Air Circulation: In the room where the mattress is airing, open all windows wide and turn on a ceiling fan or box fan to create a strong cross-breeze. An air purifier with a carbon filter can also help absorb some of the VOCs.
- Bake with Sunlight (Caution for some materials): The heat from direct sunlight can help speed up the release of VOCs. If you can place the mattress near a sunny window, this is beneficial. However, be cautious with natural latex, as prolonged direct sunlight can cause it to yellow and deteriorate.
- Use Baking Soda: Sprinkle a generous layer of baking soda over the surface of the mattress. Baking soda is a natural deodorizer that can help absorb odors. Let it sit for several hours, or even overnight, then vacuum it up thoroughly using an upholstery attachment. This is particularly effective for older mattresses with odors from spills or sweat.
- Walk or Roll on the Mattress: Gently walking or rolling on a foam mattress can help compress and release trapped air, thereby speeding up the off-gassing. This can also help to break in the foam and make it more comfortable.
Comparison of Mattress Types for Airing Out
| Mattress Type | Primary Odor Cause | Typical Airing Time | How to Speed Up |
|---|---|---|---|
| Memory Foam | Synthetic foams, adhesives | Up to several weeks | Maximize ventilation, use baking soda, walk on it |
| Hybrid | Foam layers, adhesives | A few days to one week | Excellent ventilation, some baking soda |
| Natural Latex | Natural rubber smell | A few days | Moderate ventilation; avoid direct sun exposure |
| Innerspring | Minimal; packaging odor | A few hours | Simple ventilation |
How to Deodorize a Used or Older Mattress
If you are dealing with odors from an older mattress, off-gassing is not the culprit. Instead, the smell is likely due to accumulated sweat, oils, spills, or even mold. Here is a simple, effective method for freshening it up:
- Strip the Bed: Remove all bedding and wash it on the hottest water setting appropriate for the fabric. Use this opportunity to run the mattress protector through the wash as well.
- Vacuum Thoroughly: Use an upholstery attachment to vacuum the entire surface of the mattress, including all seams and crevices. This removes dust, skin flakes, and other particles.
- Deodorize with Baking Soda: Lightly sprinkle the entire surface of the mattress with baking soda. For best results, let it sit for a few hours, or even a full day, to absorb odors and moisture. You can add a few drops of a calming essential oil like lavender for a pleasant scent. After it has sat, vacuum it all up.
- Apply Natural Sunlight: If you can move the mattress outside or place it in a sunny spot indoors, let it bake in the sun for several hours. The UV rays are a natural disinfectant and will kill odor-causing bacteria. Always check the weather to avoid rain or excessive humidity.
The Role of Certifications and Long-Term Health
When shopping for a new mattress, understanding what certifications mean can give you peace of mind. A CertiPUR-US® certification, for example, indicates that the foam was made without ozone depleters, certain heavy metals, formaldehyde, or phthalates, and that the foam has low VOC emissions. This ensures a healthier indoor air environment from the start.
While low-level, temporary off-gassing is generally considered safe, choosing products with these certifications can significantly reduce your exposure. For those with respiratory sensitivities, or if you simply want the cleanest sleep possible, investing in a mattress with these certifications is a wise choice. A great resource for exploring different mattress options and their impact on sleep is the Sleep Foundation, which provides in-depth articles on off-gassing and material safety.
Conclusion
Understanding how long does it take for a mattress to air out empowers you to be proactive in preparing your new bed for a healthy and comfortable night's sleep. While the initial off-gassing odor is temporary and mostly harmless, good ventilation is the key to speeding up its disappearance. Following simple steps like unboxing promptly, maximizing air circulation, and utilizing baking soda can make a significant difference. By taking the time to properly air out your mattress, you can ensure a fresh and healthy sleep environment for years to come.
