Volatile Organic Compounds (VOCs) are carbon-containing chemicals that easily vaporize into gases at room temperature, readily evaporating from solids and liquids. VOCs are widespread, found in many products and environments. While some have distinct odors, their absence does not mean VOCs are not present.
Common Indoor Sources
Indoor environments often have higher VOC concentrations than outdoors, sometimes up to ten times greater. This is due to continuous “off-gassing” from household items. New products often off-gas more initially, a process that can last for weeks or years.
Paints, varnishes, and adhesives release VOCs during application and drying. Some paints continue to off-gas for years. New furniture, especially items made from pressed wood or polyurethane foam, can emit significant VOCs, including formaldehyde.
Cleaning supplies, disinfectants, air fresheners, and personal care products are substantial indoor VOC sources, releasing chemicals during use and storage. Some products contain fragrances that mask VOC presence.
New carpets, vinyl flooring, and other floor coverings off-gas VOCs for about a month after installation. Materials like vinyl or treated hardwood may continue to emit formaldehyde. Cooking and fuel-burning appliances like gas stoves also release VOCs indoors.
Outdoor and Natural Sources
VOCs are prevalent outdoors, originating from human activities and natural processes. Industrial facilities are significant sources, with emissions from manufacturing plants, petrochemical operations, and refineries releasing various VOCs, including BTEX compounds.
Vehicle exhaust from cars, trucks, and motorcycles contributes substantially to outdoor VOC levels. Beyond combustion, evaporation from petroleum fuels and gas leaks also release VOCs. Outdoor VOCs can migrate indoors through open windows or poorly sealed building structures, affecting indoor air quality.
Natural sources also contribute to atmospheric VOCs. Trees and other plants naturally emit these compounds. Forest fires and the decomposition of organic matter in anaerobic conditions (e.g., moors or composting) are additional natural processes that release VOCs.
Reducing Exposure
Minimizing VOC exposure involves improving ventilation. Regularly opening windows and doors allows fresh air to circulate, diluting and expelling indoor VOCs. Using exhaust fans in kitchens and bathrooms further aids in removing pollutants.
Selecting low-VOC products is an effective strategy. When purchasing paints, varnishes, cleaning supplies, or furnishings, look for labels indicating low-VOC or VOC-free content. While no product is entirely free of VOCs, choosing those with reduced emissions can significantly lower indoor concentrations. For new items like carpets or furniture, allowing them to off-gas outdoors in a well-ventilated area (e.g., a garage or shed) for several days before bringing them inside can help reduce initial VOC release.
Proper storage of chemicals is important. Ensure all containers of paints, solvents, adhesives, and other household chemicals are tightly sealed to prevent leakage. Avoid storing open containers in living spaces; instead, store unused chemicals in a garage or shed to contain emissions. Maintaining optimal indoor humidity (ideally 30-50%) can discourage VOC release, as higher temperatures and humidity accelerate off-gassing.