Every year, around this time, a debate arises about the world’s most common decoration: the Christmas tree.Should it be natural or artificial? There are strong arguments to defend both options. From an environmental perspective, a natural tree is better, although it may seem otherwise. (Emits less CO2 than producing artificial), but From a health perspective, live trees can affect the air chemistry in the home and, in turn, affect people with allergies. and those who are sensitive Volatile Organic Compounds (VOC).
A recent study analyzed the effects of natural trees used for Christmas on the health of homes and their inhabitants. Many families choose live trees because of the fresh scent they produce. However the smell comes from VOCsthese are still chemicals. Until now, little was known about how much each tree emits and whether they have any health effects.
“Our nose is a good chemical sensor,” says Dustin Poppendieck, an environmental engineer at the National Institute of Standards and Technology (NIST). “We knew these trees were emitting something, and we wanted Investigating which chemicals are emitted and in what quantitiesand consider it in the context of other sources of chemicals in the home,” he explains.
To dispel these doubts, Poppendieck and his NIST colleagues took a spruce tree and sealed it in a room. They then measured the amount and type of VOCs it emitted over 17 days. Moreover Investigated whether VOCs react with other components of indoor air to form new compounds.
Cough and throat irritation
The team’s findings, published recently in the journal Indoor Environments, reveal that the fresh smell commonly associated with Christmas trees comes from a group of VOCs called monoterpeneIt is also found in scented products, air fresheners, candles, and some personal care products.
Outdoors, conifers, the group of trees that includes most Christmas trees, release monoterpenes and can affect outdoor air quality. But little is known about the amount of monoterpenes released when a tree is cut down and placed inside a home.
Previous studies have shown that Monoterpenes can react with ozone, which is formed in soil through chemical reactions with light, causing symptoms such as cough and throat irritation..
Ozone also easily reacts with other chemicals in the air to form new compounds. Therefore, the researchers were interested in seeing the effects in the presence of an indoor tree.
By placing the tree in an environmentally controlled chamber, they were able to measure the chemicals emitted in real time using a technique known as proton transfer reaction mass spectrometry (PTR-MS), which can detect organic compounds in the air.
Researchers simulated home atmosphere. They decorated the tree with a typical Christmas lighting setup and lit it with bright lights to mimic the day-night cycle. They turned off the lights every 12 hours and watered the tree every day. They introduced outdoor air at a rate specific to homes and They continuously measured chemicals in indoor air.
Reactive chemicals
Monoterpenes were the most abundant VOCs emitted by the tree. 52 different ones were identified. They peaked on the first day, then decreased significantly on the third day. Its concentration was initially on par with a plug-in air freshener or a newly built house. But then it quickly dropped to almost 10 times its original amount, Poppendieck notes.
The scientists then injected ozone into the room to see how it affected the chemistry of indoor air. They discovered that ozone reacts with monoterpenes to form byproducts such as: formaldehydeother types of VOCs and other reactive chemicals.
With the introduction of ozone, monoterpene concentrations further decreased while formaldehyde levels increased, which had an impact on indoor air chemistry. But, the amount of formaldehyde created was relatively smallabout one part per billion. It is a much lower concentration than normal in most homes..
The result is For people sensitive to VOCs, Christmas trees can be a possible cause of watery eyes and noses in the first few days of the live tree inside the house..
In this case Poppendiec suggests: open a window next to the tree To reduce exposure to VOCs. There may also be freshly cut trees leave it outdoors or in the garage for three days before bringing it homegiven Emission intensity naturally decreases over time.
In any case, According to Poppendieck, “for most people, planting a freshly cut natural tree in the home should not be a major concern.”. The investigator assured that he would continue to have a natural Christmas tree in his home.
New method: trees for rent
on the subject environmental impactAlthough at first glance it may seem like a purchase is being made artificial tree More respectful to the planet, It is most likely made from PVC, which produces greenhouse gases (GHG) during the manufacturing process and is not biodegradable..
Recent estimates by independent organizations have concluded that: Making an artificial tree two meters high produces approximately 40 kilograms of carbon dioxide (CO2), while a natural tree of similar size produces “only” 3.5 kilograms of this gas. So much so that the artificial one would have to be reused for twelve Christmases so that its environmental impact would be lower than the natural one.
Of course advocates ‘fake’ trees They also emphasize that: money is saved Since they can be reused, they do not contain pollutants such as fungi and do not pollute homes and some places. They may smell like pine just like the ‘real’ ones.
In contrast, supporters live trees They emphasize that much of what is purchased for Christmas is grown by local producers, so their purchases are representative. support local economies. Meanwhile, almost 90% of the artificial ones come from China.
Already available in the UK Some companies advocating a new method: tree rental They are grown in special pots that allow them to be dug up and replanted every year. Customers who want to use one of these trees at Christmas pay a deposit and receive instructions to keep their tree in good condition, such as keeping it away from heat sources or watering it daily.
Reference report: https://www.sciencedirect.com/science/article/pii/S2950362023000024?via%3Dihub
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