The scent of freshly cut or installed wood, often perceived as a pleasant, natural aroma, results from chemicals being released into the air. This “new wood smell” raises the question of whether this fragrance poses a health risk. Although the compounds are organic and tree-derived, their concentration in indoor air, especially in new construction or woodworking environments, can be significant enough to cause adverse reactions.
The Chemistry Behind the Aroma
The characteristic odor of wood originates from the release of volatile organic compounds (VOCs), which easily vaporize at room temperature. Wood naturally contains a wide array of these compounds, known as extractives, with the composition varying significantly by tree species. Softwoods, such as pine and spruce, emit the highest concentrations of VOCs, typically composed of 70 to 90% volatile terpenes.
Terpenes are organic compounds produced by plants that serve as a natural defense mechanism against insects and pathogens. Common terpenes like alpha-pinene, beta-pinene, and limonene create the sharp, resinous scent associated with many conifers. Aldehydes, such as hexanal and pentanal, are also released, particularly from hardwoods or as products of wood degradation. The release of these VOCs is accelerated when wood is freshly cut, sanded, or exposed to changes in temperature and humidity.
Acute Health Reactions to Wood VOCs
Exposure to VOCs released from new wood can lead to immediate, short-term health effects, primarily affecting the sensory and respiratory systems. Common acute symptoms include irritation of the eyes, nose, and throat membranes, manifesting as burning sensations, coughing, or sneezing. These reactions are often due to the irritant properties of terpenes and aldehydes at high concentrations.
Individuals may also experience systemic symptoms, such as headaches, dizziness, and fatigue, especially when exposed to high concentrations in poorly ventilated spaces. These acute effects are generally temporary and subside once the person leaves the contaminated environment. For most healthy people, the risk from general wood VOCs is irritation rather than systemic toxicity under typical, low-level exposure.
A more concerning reaction is sensitization, where the immune system recognizes a chemical as a threat after repeated exposure. This can lead to allergic responses like asthma or rhinitis, which may become progressively more severe with continued exposure. The potential for sensitization highlights why ventilation and exposure control are crucial when working with wood.
Risks Associated with Specific Wood Species
The danger level is highly dependent on the specific chemical profile of the wood species. Certain woods contain unique compounds that are potent sensitizers or irritants, making them more hazardous than common construction lumber.
Western red cedar, for example, is a documented cause of occupational asthma due to plicatic acid. Exposure to this acid can cause or worsen asthma and rhinitis, with damage that may be progressive over time.
Exotic hardwoods, such as cocobolo, are notorious for their high sensitizing properties, often causing severe allergic contact dermatitis and respiratory problems. The primary allergens in cocobolo and other rosewoods are quinones, which are toxic biocides produced by the tree for defense. These quinones, including obtusaquinone, can cause a severe rash similar to poison ivy upon skin contact and lead to asthma-like symptoms if the dust is inhaled.
Ebony is another wood known to contain high levels of toxins, and its fine dust can trigger respiratory difficulties and severe allergic reactions. The chemicals in certain tropical woods can cause symptoms like giddiness, cramps, and irregular heartbeat if absorbed into the body. These potent, species-specific chemical compounds distinguish the risk of exotic woods from the general irritation caused by common wood terpenes.
Strategies for Reducing Exposure
Minimizing exposure to wood VOCs and dust is best achieved through practical, preventative measures, especially when working with or installing new wood. The most effective strategy is ensuring adequate air exchange where the wood is located. Opening windows and using exhaust fans helps to dilute the concentration of airborne chemicals and dust particles, preventing buildup.
Allowing new wood products to “off-gas” in a well-ventilated area before prolonged exposure can significantly reduce the initial high emission rate of VOCs. The highest chemical release typically occurs immediately following processing, decreasing over time as the compounds dissipate. Another effective method is using sealants or low-VOC finishes on the wood surface. Encapsulating the wood with a barrier finish can substantially reduce the rate at which internal VOCs escape into the surrounding air.