Off-gassing describes the release of airborne chemicals from products and materials into the surrounding environment, significantly affecting indoor air quality. This phenomenon occurs when volatile compounds, trapped within liquids or solids during manufacturing, slowly evaporate into the air over time. The characteristic “new car smell” or the odor from fresh paint are common indicators of this chemical release. Since modern, energy-efficient buildings are often tightly sealed, these emissions can accumulate indoors at high concentrations, raising concerns about potential health impacts.
Understanding Volatile Organic Compounds
The chemicals released during off-gassing belong to a class of substances known as Volatile Organic Compounds (VOCs). These organic chemicals vaporize easily at typical indoor temperatures due to their low boiling points. VOCs are responsible for the initial, strong odors associated with new products.
A separate group, the Semi-Volatile Organic Compounds (SVOCs), possess lower volatility and a higher boiling point. While VOCs are released quickly and remain primarily in the air as gases, SVOCs are released slowly over months or years. These compounds, which include flame retardants and plasticizers, tend to condense and adhere to indoor surfaces, such as dust, furniture, and fabrics, creating a persistent, long-term exposure risk.
Common Sources of Off-Gassing in the Home
Common household items and building materials are significant sources of these chemical emissions. New furniture is a major contributor, particularly items made from pressed wood products like particleboard and medium-density fiberboard (MDF), which often use adhesives that continuously release formaldehyde. Synthetic foam cushions and mattresses can release SVOCs, such as organophosphate or brominated flame retardants, which migrate out and settle in house dust.
New carpets and vinyl flooring can off-gas VOCs like styrene and 4-phenylcyclohexene from the synthetic fibers, backing, and installation adhesives. Paints, varnishes, and sealants also release solvents and other VOCs for weeks or months after application. The rate of off-gassing is accelerated by warmer temperatures, meaning a new item placed in a sun-warmed room releases chemicals more rapidly than one kept in a cooler environment.
Health Impacts of Exposure
Exposure to off-gassed VOCs and SVOCs can result in a range of effects, categorized as either acute or chronic depending on the chemical and exposure duration. Acute exposure, occurring immediately or shortly after exposure to high concentrations, frequently causes irritation of the mucous membranes. Symptoms include burning eyes, sore throat, rhinitis, headaches, and nausea, which often resolve quickly once the source is removed or the air is cleared.
Chronic exposure, involving continuous or repeated contact with lower levels of chemicals, raises concerns for long-term health. Certain VOCs, such as formaldehyde, are classified as human carcinogens and have been linked to respiratory tract injury and nasal mucosal lesions. Prolonged exposure can also affect the central nervous system, leading to fatigue, difficulty concentrating, and neurological issues.
SVOCs, including phthalates and some flame retardants, pose a chronic risk because they function as endocrine-disrupting chemicals. These compounds can interfere with the body’s hormonal systems, mimicking or blocking natural hormones, such as those regulating the thyroid. This disruption is concerning for vulnerable populations, like children and the elderly, as it can affect reproductive, developmental, and neurological function.
Strategies for Reducing Indoor Air Contaminants
One effective strategy for mitigating off-gassing is to maximize ventilation, especially when introducing new products or after renovation. This involves opening windows and using exhaust fans to increase the air exchange rate, allowing released VOCs to dissipate outdoors. New items, such as furniture or mattresses, should be “aired out” in a garage or well-ventilated space for several days or weeks before being brought into the main living area.
Choosing certified low-emission products is a preventative measure that reduces the contaminant source. Consumers should look for third-party certifications like UL GREENGUARD or CRI Green Label Plus, which verify that a product has met strict standards for low VOC and total chemical emissions. For instance, the UL GREENGUARD Gold standard enforces low limits for total VOCs and requires compliance with the stringent California Section 01350 for chemical emissions.
Air purification can also manage airborne VOCs using activated carbon filters. These filters are not mechanical strainers like HEPA filters; instead, they operate through adsorption. The activated carbon material possesses a highly porous structure with a vast internal surface area, which physically attracts gaseous VOC molecules and traps them within the pores, effectively removing them from the air.