Christmas Trees and Indoor Air Chemistry: A Surprising Discovery

Image: Christmas Tree Impact on Indoor Air Chemistry

Christmas trees have been a beloved tradition for many families during the holiday season. However, a recent study conducted by the National Institute of Standards and Technology (NIST) has revealed that live Christmas trees can affect indoor air chemistry. The researchers found that live Christmas trees emit volatile organic compounds (VOCs), which can react with ozone to form byproducts.

The study involved placing a common type of Christmas tree, a Douglas fir, in a sealed chamber for 17 days. The researchers monitored and measured the chemicals emitted by the tree during this period. They discovered that monoterpenes, a group of VOCs responsible for the pine smell, were the most abundant chemicals emitted. These monoterpenes can react with ozone, leading to the formation of byproducts such as formaldehyde, another type of VOC.

The concentration of monoterpenes peaked on the first day and then diminished significantly by the third day. However, the amount of formaldehyde created was relatively small, at around one part per billion. Typical U.S. houses have formaldehyde concentrations ranging from 20 to 30 parts per billion.

For people who are sensitive to VOCs, Christmas trees could be a potential cause of watery eyes and noses, especially when initially brought indoors. To reduce exposure, the researchers suggest opening a window near the tree or leaving the tree outdoors or in a garage for three days before bringing it inside. The emission strength of the tree naturally decreases over time.

However, for most people, this should not be a major concern. Dustin Poppendieck, an environmental engineer at NIST, emphasizes that he will still have a Christmas tree in his house.

This study provides valuable insights into the impact of live Christmas trees on indoor air chemistry. While the effects may not be significant for most people, it is essential to consider the potential health impacts for those who are sensitive to VOCs.