If you saw a headline proclaiming that “Your House is Killing You. Here are 7 Ways to Stop It,” you’d probably pause to glance through it, right? This is the kind of alarmist rhetoric that surrounds the ubiquitous presence of volatile organic compounds (VOCs) in our homes.
It is important, though, to consider just how dangerous these chemicals are that leach into the airspace in our homes, and how long it takes for them to dissipate.
How long does off-gassing take? Off-gassing takes anywhere from 72 hours to the lifetime of the product. For example, The EPA recommends that you allow off-gassing of carpets to take place in a well-ventilated environment for at least 72 hours after installation. Paint can off-gas for six months, and particle board for up to twenty years.
The duration and effects of off-gassing depend on many variables such as the chemical itself, its concentration in the product and, perhaps most importantly, the person exposed to the off-gassing. We will address these factors and mention some of the vast number of products and materials that require off-gassing.
Off-Gassing/Out-Gassing: What’s the Difference?
First, let’s take a quick look at terminology. Merriam-Webster defines the verb “off-gas” as “to give off a typically harmful gas.” Off-gassing, then, is the emission of poisonous or unpleasant gases from a material. To out-gas, on the other hand, means “to remove gases from,” usually by heating.
Writing for Molekule, and air purifier manufacturing company, Catherine Poslusny makes the following distinction between off-gassing and outgassing: off-gassing relates to “indoor air quality and manufactured household products and furniture,” while outgassing refers more often to the processes engineered in a laboratory to cause these reactions (source).
But the distinction is academic. A quick check on Google Ngram Viewer shows a slight preference for the use of outgas, with both terms peaking in usage between 1990 and 2000 before experiencing a sharp decline in usage.
We’ll come later to why this decline might be. For convenience, we’ll use the more common term “off-gassing” to refer to the process that occurs when (usually) newly manufactured items in our homes release volatile organic compounds (VOCs) and other chemicals into the surrounding air.
How Long Does Off-Gassing Take?
We’ve already established that answering this question is like asking, “How long is a piece of string?” It depends. There are a host of products, materials, and different chemicals that have an impact on the quality of the air in our homes.
Another major obstacle to answering this question with any assurance of accuracy is that there seems to be a reluctance on the part of manufacturers of household furnishings, products, and appliances to commit to research and data to support the science of off-gassing.
In other words, they don’t seem to want to tell us. The reason for this reluctance is self-evident: off-gassing of materials and products is noxious. Yet another anomaly is that the evidence of just how noxious these materials are is scarce. When not scarce, the evidence is often contradictory.
One source might claim that materials off-gas at their most noxious “for a few weeks” after manufacture, but the same source will usually hedge their bets by saying that it “isn’t that cut and dry” (source).
While it is true what the chemical companies claim, that everything from flowers to fruit off-gasses — otherwise we wouldn’t smell anything — the fumes some things emit are more harmful than others. Chemicals, plastic, and adhesive fumes are the worst.
The most accurate timing we can establish for the duration of off-gassing is that much of it happens when you first remove the plastic covering from your new product or piece of furniture. Therefore, if possible, you should do this outdoors where the fumes may dissipate freely rather than into your indoor air.
Alternatively, ask the product vendor to air the item for a few days (or longer, if practical) in their warehouse, a fairly common practice known as “warehousing.” If that’s not an option, consider unpacking and airing your new purchase in a garage or other unoccupied space.
One of the worst offenders for off-gassing is carpet (source), especially wall-to-wall carpeting. Most of the off-gassing happens within the first few months but, as already mentioned, this process can continue for more than five years.
This is due to the carpet material: 95 percent of synthetic carpets are made from nylon fiber with a polypropylene/latex backing. Add to this the noxious glues used as an adhesive when installing the carpet. These glues typically contain benzene and toluene, two of the most toxic VOCs.
So, how widespread is the phenomenon of off-gassing? The US Environmental Protection Agency (EPA) claims that a wide variety of products emit concentrations of VOCs, numbering in the thousands and are up to ten times higher indoors than outdoors (source).
Seventy-two hours (three days) is the EPA’s recommendation for the thorough ventilation of a newly-carpeted area. You can achieve the best ventilation by opening windows and doors and allowing outside air to circulate, preferably assisted by a fan to drive fumes out.
You should also use fans during installation and for a few weeks afterward.
Mattresses are another source of dangerous off-gassing because they are usually made from polyurethane foam, a source of toluene, and are often treated with stain-, water- and wrinkle-resistant chemicals which contain formaldehyde.
To make matters worse, some states (e.g., California) treat mattresses with flame retardants, which add to the chemical load.
The commonly used PBDEs (polybrominated diphenyl ethers) used as flame retardants are particularly toxic, and scientists have linked them to neurological and developmental damage. This damage leads to learning/hearing/memory deficits, delays in sensory-motor development, and changes in behavior.
This is not the sort of environment in which you want your kids to sleep for eight hours at night.
The “new mattress” smell may only last a week or so, but that doesn’t mean that the off-gassing has ended. It may continue for the lifetime of the product, albeit in smaller doses, which for the majority of people may have little or no health side-effects.
Still, it is not something which you want to treat lightly when it comes to the health and development of your newborn or growing children. One alternative would be an “organic” mattress (source).
Just to complicate matters, some VOCs are odorless. There are also compounds known as Semi-Volatile Organic Compounds (SVOCs), which have received less attention because they are more difficult to measure.
They are just as important as VOCs, however, because they tend to off-gas more slowly and consistently over the life of the product.
Over time, off-gassing may be the cause of childhood allergies, asthma, and even some cancers. But again, the problem is that there has been so little research on the short- and longer-term impact of off-gassing. It’s all too vague. We are only told that VOCs dissipate over time as the chemicals vaporize.
Paint, for example, “dissipates fairly quickly with most off-gassing occurring during the first six months after application” (source). When it comes to polluted indoor air, “fairly quickly” and “six months” are not encouraging terms when taken together.
But don’t let that stop you from repainting the bedrooms. Particleboard— “engineered wood” or “pressed wood” from which much of today’s cabinets and furnishings is manufactured—may continue to off-gas for 20 years or more.
Particleboard is a composite of wood particles and chemical adhesives or resins that bind the wood particles together. It is these chemical adhesives and resins that release VOCs and SVOCs into the atmosphere.
So, there is no short answer as to how long a particular product may off-gas. You may be fairly confident, however, that depending on the product, its chemical makeup, and the environment in which it is housed, VOCs off-gas throughout the life of the product (source).
A significant amount of this happens in the first several years of the product’s lifespan, but just because you can’t smell it doesn’t mean that it is not still happening.
Main Sources of Off-Gassing in Homes and Buildings
The chemicals mainly responsible for off-gassing are a large group of elements (known as VOCs and SVOCs), which include formaldehyde, benzene, ammonia, toluene, polyurethane foam, and most paints, stains, and sealers.
As already mentioned, furnishings made of synthetic materials—which account for most of our product ranges today—are some of the main culprits. Cabinets, sofas, mattresses, and tables all off-gas from the finishes, paint, glue, and synthetic fabrics from which they are manufactured.
A host of floor coverings are also responsible and pose a particular threat if infants and younger children are crawling around at floor level.
We’ve already discussed synthetic carpets, but equally noxious is the polyvinyl chloride (PVC) found in linoleum, upholstery, and shower curtains—PVC is pretty much everywhere, so eliminating it from the home could be quite a mission.
Then, there are a host of household cleaners and products which emit VOCs. One of the most useless of these is air freshener, which does nothing but spray chemicals into the indoor air. The same goes for many other household cleaning sprays.
In fact, new chemical products have blossomed since World War II. Estimates are that 80,000 new chemical compounds have been developed since then, only a relative handful of which are properly regulated.
Electronic equipment is another often unidentified source of off-gassing. Computers and printers release VOCs and ozone, especially from the insulation materials containing flame retardants, exacerbated by the heat generated during the operation of the equipment, especially when new.
On a more encouraging note, one of the reasons why the terms “off-gassing” and “outgassing” have dropped off the Ngram Viewer radar is that some degree of regulation and increased awareness of the dangers of off-gassing has led to a reduction in the widespread use of VOCs and SVOCs in new products, but not altogether.
Sealed Homes and Buildings
As buildings become more airtight in order to conserve heating and cooling energy, the risk of lowered indoor air quality (IAQ) increases.
Fortunately, most HVAC (heating, ventilation, and air conditioning) systems have kept pace with the demand for unpolluted indoor air. The days of Sick Building Syndrome leading to Building Related Illness (BRI) may be a thing of the past.
How to Control Off-Gassing
Though off-gassing is inevitable with many products, there are ways to mitigate the problem and speed up the process.
Giving the product or material time to off-gas is probably the most effective way of controlling the effects of off-gassing. Although most products continue to off-gas through the course of their useful lives, the most hazardous effects do diminish over time.
Allowing time to off-gas in the early days or weeks before bringing a new product indoors means that we must store the product in a space away from human exposure.
Warehousing, venting in an unoccupied garage or spare room, and unpacking new products outdoors to allow the initial off-gas to dissipate, are all sensible short-term solutions.
Since off-gassing is a process of evaporation of volatile chemicals at normal atmospheric pressure and temperature, warming the ambient temperature of the place where the product is off-gassing should speed up the process. Ideally, this can be done using heaters or fans, or a combination of the two.
This brings us to the third and most important means of controlling off-gassing; ventilation is key to any off-gassing activity.
This means that for the first few days—or longer, if possible—you should place the product in a well-ventilated space. Keep windows and doors open to allow circulation of fresh outdoor air, assisted by fans to maintain circulation.
Modern HVAC systems in sealed buildings have an extraction system that facilitates the venting of noxious airborne VOCs. However, it may be advisable to allow fittings and fixtures in sealed buildings to off-gas off-site before installation, in order to allow the worst of the VOCs to dissipate.
For tips on how long it takes to properly ventilate a domestic environment, read our article, “How Long Does it Take to Exchange Air in a House.”
Health Issues with Off-Gassing
Some people will experience few, if any, adverse symptoms from off-gassing—in fact, they may even enjoy the “new carpet” smell while it lasts.
Others may experience dizziness, nausea, headaches, and ear/nose/throat irritations. Of more concern, scientists have associated some of these chemicals with the development of leukemia, lymphomas, and cognitive impairment.
Like so many other circumstances that impact our health, the young and the elderly are particularly at risk due to off-gassing.
This is, in part, because the young and old tend to spend a disproportionate amount of time indoors and are, therefore, more exposed to indoor air quality. The additional risk is also because their immune systems are still developing (in the young) or compromised (in the elderly).
Particular caution is, therefore, required for these age groups. Exposure to VOCs may lead to the long-term development of allergies, skin irritations, or bronchial issues such as coughing and asthma in the young.
It is a real concern, too that, in most products, off-gassing continues for years, and, in some cases, accumulates in the body over time.
For example, scientists believe that PBDEs (flame retardants) damage the hormone and immune system. The Environmental Working Group published an alarming article on this topic entitled “Caution: these seven household items may feminize baby boys.”
While the short-term effects of exposure to VOCs in off-gassing may be limited to minor irritation of the eyes, nose, and throat, with perhaps some nausea, dizziness, or headache, these symptoms usually disappear quickly when exposure is reduced, or when the sufferer gets out into the fresh air.
Longer-term exposure is more problematic. As noted, the consequences of long-term exposure may include some forms of cancer, kidney or liver damage, or disruption of the nervous system.
Fortunately, most people recognize the common-sense hazards of breathing in a cocktail of chemicals in the air and take the necessary precautions to avoid and ventilate, especially when it comes to children and the elderly. Hospitalization may only be necessary if there are underlying health issues aggravated by off-gassing.
Increasing awareness of the dangerous effects of off-gassing has led to at least two positive outcomes.
Firstly, the use of hazardous materials in the manufacture of products has been reduced and increasingly regulated by agencies such as the EPA (for drinking water and outdoor air) and the Occupational Health and Safety Administration (OSHA, for the workplace).
Unfortunately, there still isn’t a great deal of regulation when it comes to the quality of the air in your home. It’s really up to you.
Secondly, consumers of these products are increasingly aware of the effects of the products which they purchase and are (when possible) making choices about what they buy based on healthier alternatives.
Starting in about the 1980s, people have become increasingly aware that off-gassing is a noxious side-effect of a vast array of products and materials present in our homes and workplaces. This has led to a search for healthier alternatives.
There is often an economic impact to these choices, in that healthier, natural alternatives may be more expensive. Wool carpets with a jute backing—or choosing natural fiber area rugs in preference to wall-to-wall carpets fixed with toxic adhesives—may come at a cost.
But for the long-term protection of the health of our families, this is a price which more and more people seem to be prepared to pay.