Researchers from the National Institute of Standards and Technology in the United States studied how volatile organic compounds released by real Christmas and New Year trees alter the air inside homes. Their findings suggest that plant emissions can form toxic byproducts under certain conditions. The work appeared in a scientific journal titled Internal Environments.
The familiar pine scent comes from monoterpenes, a class of volatile organic compounds that also show up in air fresheners, candles, and some personal care items. Until recently, scientists did not fully understand how these monoterpenes interact with other substances present in indoor air.
In two phases, researchers placed a decorated Douglas fir in a controlled room for 17 days to quantify which VOCs were emitted and in what amounts, using mass spectrometry to identify and measure them. They then examined how these compounds reacted with other indoor air components, including oxidants and sunlight-driven processes.
The experiments revealed that monoterpenes released from the wood can react with ozone present in indoor air, a reaction driven in part by ultraviolet light. This interaction produces a suite of secondary products, including formaldehyde and other reactive chemicals. Over the course of the study, the concentration of monoterpenes declined while formaldehyde levels rose, illustrating a dynamic chemical balance in a real room environment.
However, the researchers emphasized that the levels observed were generally very low. Formaldehyde concentrations varied but were reported to be only around one part per billion, a figure that is substantially lower than typical indoor residential ranges documented in surveys and building assessments. The takeaway is not to panic, but to understand the chemistry at play and how it may differ by setting and ventilation.
Another key finding was that the largest amounts of monoterpenes were released in the first three days after harvest. As a practical measure, the study suggests that a purchased Christmas tree could be kept in a garage or on a balcony for about three days before bringing it indoors. This pre-ventilation period helps reduce the concentration of VOCs in the living space once the tree is installed.
Additional observations from other experts noted that seasonal decorations can influence more than the scent and ambiance. In some contexts, there have been concerns about the potential for wireless signals to be affected by certain decorative materials or arrangements, though these effects are typically minor and highly dependent on the specific setup and conditions.
In summary, real trees do emit VOCs that can interact with indoor air chemistry. The audible message for households is to consider airing out a new tree before bringing it inside and to maintain good room ventilation during the initial days after installation. This approach helps dilute any transient compounds and supports healthier indoor air throughout the holiday season. [citation]