Scientists have determined how Christmas trees affect the chemical composition of indoor air.

During the holiday season, many families enjoy not only having a live Christmas tree in their homes, but also the fresh scent it creates. This odor comes from chemicals called volatile organic compounds (VOCs).

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However, little is known about how much is released and whether they have any health effects. Scientists from the National Institute of Standards and Technology (USA) undertook to check this, the university’s press service reports.

Our nose is a good chemical sensor, scientists emphasize. “We know that these trees are emitting something, and then the question becomes: how big a source is it?” We wanted to explore exactly what chemicals were released and in what quantities and put this in context with other sources of chemicals in the home.

To answer these questions, scientists:

1. took a common Christmas tree—the Douglas fir, common in North America and some forests in Europe—and sealed it in an environmentally controlled chamber;
2. they then measured the amount and type of VOCs it emitted over 17 days;
3. they also examined whether VOCs reacted with other components of indoor air to form new compounds.

The fresh smell commonly associated with Christmas trees comes from a group of volatile organic compounds called monoterpenes, also found in air fresheners, candles and some personal care products, the article notes. — Outdoors, conifers, which include most Christmas trees, produce monoterpenes and these can affect outdoor air quality.

However, little is known about how many monoterpenes are released when a tree is cut down and placed indoors.

It is also known that monoterpenes can react with ozone, which can cause symptoms such as coughing and throat irritation. Ozone easily reacts with other chemicals in the air to form new compounds.

Therefore, the researchers were interested to see the effect of ozone in the presence of indoor wood.

It is noted that in their experiment, the researchers simulated a home environment:

• decorated the tree with typical holiday lights and turned on bright lights to simulate the cycle of day and night. They turned off the lights every 12 hours and watered the tree every day;
• they brought in outside air at a rate typical of households and continuously measured the chemicals in the indoor air.

As a result, it turned out that:

• monoterpenes were the most common VOCs emitted from the tree. They peaked during the first day and then dropped significantly on the third day. Thus, their concentration was initially at the same level as in a regular air freshener or in a new home, and then quickly decreased to almost 10 times the initial level. The researchers found 52 different types of monoterpenes.
• the researchers then introduced ozone into the chamber to see how it affected indoor air chemistry. They discovered that ozone reacts with monoterpenes to form byproducts such as formaldehyde, another type of VOC, as well as other reactive substances;
• monoterpene concentrations further decreased with the introduction of ozone, while formaldehyde levels increased, showing an effect on indoor air chemistry;
• however, the amount of formaldehyde produced was relatively small—about one part per billion. In typical homes, formaldehyde concentrations range from 20 to 30 parts per billion.

For people sensitive to VOCs, Christmas trees may be one possible cause of watery eyes and noses, especially when they are first brought indoors, the article notes.

In this case, scientists advise:

• open the window near the Christmas tree, you can reduce the influence of harmful substances;
• Freshly cut trees can be left outdoors or in the garage for three days before bringing them indoors, as the spreading power of chemicals naturally decreases over time.

But for most people, this shouldn’t be a big concern, one of the researchers noted. “There will still be a Christmas tree at my house.”

Source: Racurs

David

I am David Wyatt, a professional writer and journalist for Buna Times. I specialize in the world section of news coverage, where I bring to light stories and issues that affect us globally. As a graduate of Journalism, I have always had the passion to spread knowledge through writing.