Can the "strong carcinogen" formaldehyde really be stopped from the source? Scientists give a new answer

One C, two H and one O, through chemical reactions, form a substance that is harmful to the human body - formaldehyde.

Figure｜Structure of formaldehyde

In our daily life , formaldehyde is almost everywhere, whether in a newly renovated house, in every corner of a public meeting room, or on surfaces ranging from carpets to toilet paper. In industry , formaldehyde is also an important compound in the manufacture of textiles, paints, and automobiles.

A colorless, odorless, irritating gas, formaldehyde has been shown to be a strong carcinogen, with even low levels of exposure linked to certain types of cancer and leukemia.

Faced with this known carcinogen, people often talk about "formaldehyde" with fear. Is there a way to inhibit the production of formaldehyde? Is there a way to remove all the produced formaldehyde?

Figure｜Plywood decoration building materials contain a lot of formaldehyde, which is one of the sources of formaldehyde indoors. (Source: Wikipedia)

A new study led by researchers at the University of Massachusetts Amherst and the University of North Texas advances our understanding of how wood in our homes and offices can emit formaldehyde above certain health limits.

The research team said the findings could help improve public health, and that their solution is an effective, low-cost way to mitigate the damage caused by formaldehyde , for which they have applied for a patent.

The research paper, titled “Formaldehyde emission from wood promoted by lignin in the presence of iron residues,” has been published in the scientific journal Green Chemistry. Yu Fu, a teaching researcher at the University of North Texas, is the first author of the paper.

A ubiquitous carcinogen

From particleboard to curtains and carpets, certain man-made household products release formaldehyde into living spaces. Wood itself also releases formaldehyde, and high-temperature wood processing releases even larger amounts of formaldehyde.

However, it turns out that wood — including wooden furniture and other wood products in our homes — releases small amounts of formaldehyde even at room temperature .

"People knew that wood would release formaldehyde at low temperatures, but no one really knew how that formaldehyde was produced," said Barry Goodell, a professor of microbiology at the University of Massachusetts Amherst and one of the paper's corresponding authors.

So why is this? The key lies in a special chemical phenomenon, which the research team describes as the "lignin-mediated Fenton reaction."

Taking wood as an example, the reaction principle is as follows:

The "lignification" (hardness and stiffness) of wood is given by a substance called "lignin", which creates tough cell walls. As trees grow in soil, they continuously absorb trace amounts of iron (one of the most abundant elements on Earth), which remains in the tree.

Later, when the trees are cut down and made into lumber by tools containing iron, such as saws and planers, more iron enters the surface of the wood. Lignin then reacts with the iron to form a highly reactive iron. When this highly reactive iron comes into contact with air, it forms a corrosive oxygen free radical that eventually combines with lignin to form formaldehyde.

The formaldehyde formed escapes from the wood, enters the air, and even into people's lungs.

The discovery suggests new understanding of the scientific question of how formaldehyde is produced from wood and wood surfaces at room temperature.

Hopefully, it will be eliminated at the source

For the research team, simply knowing the cause of formaldehyde production is not enough. They also hope to inhibit the production of formaldehyde based on this research result.

“Once we know how the lignin-mediated Fenton reaction occurs and how it is carried out in wood,” Goodell said, “we have some ideas about how to prevent the reaction from happening.”

Goodell speculates that antioxidants may be able to prevent the production of oxygen free radicals, and simple "chelators" may also bind iron, thereby preventing it from reacting with the surrounding environment.

(Source: Pixabay)

To test their hypothesis, Goodell and his team conducted a series of experiments. They found that by simply mixing these antioxidants and chelating agents with wood, or in some cases spraying them on the surface of wood, the level of formaldehyde release was mitigated and reduced to safe levels . In addition, they also saw a reduction in formaldehyde in commercial wood products.

" This invention is simple, low-cost and can be easily integrated into existing wood processing lines to produce high-quality, environmentally friendly wood products ," said Sheldon Q. Shi, a professor of mechanical engineering at the University of North Texas and one of the corresponding authors of the paper. "The formaldehyde control method we developed should also be safe in the home, and people can easily use indoor systems to improve air quality."

In the future, the research team will work to develop products that can be used in homes and workplaces to reduce the levels of formaldehyde released from wood products in these environments.

Some truths about formaldehyde

Currently, formaldehyde is one of the most common indoor air pollutants. There are more than 3,000 different building materials that contain formaldehyde, and the main sources are fiberboard, plywood, sound insulation board, styrofoam and other decoration materials.

Formaldehyde is irritating to the skin and mucous membranes, such as the throat, eyes and nasal cavity, causing edema, inflammation, ulceration, and even serious diseases such as nasopharyngeal cancer. Skin that has come into contact with formaldehyde may become allergic, and in severe cases may even lead to hepatitis, pneumonia and kidney damage. Formaldehyde is even more harmful to infants and pregnant women, and can cause the unborn fetus to stop growing and developing, heart and brain stunting, and even fetal malformations and miscarriages.

Therefore, people often talk about "formaldehyde" with fear, but what they don't know is that only long-term exposure to high concentrations of formaldehyde will show significant carcinogenic effects. (However, the lower the formaldehyde concentration we are exposed to in daily life, the safer it is.)

In addition, smelling cannot determine whether the surrounding formaldehyde exceeds the standard . Formaldehyde is a colorless, odorless, irritating gas, but the odor threshold of formaldehyde (that is, the minimum concentration that people can smell) is basically lower than the minimum concentration that most people can smell.

Moreover, there is basically no furniture that does not release formaldehyde . Almost every piece of furniture includes boards, adhesives, etc. These parts may release formaldehyde, and some wood itself also contains formaldehyde.

Another truth is that the effect of green plants in absorbing formaldehyde may be very limited . Although plant leaves can absorb formaldehyde, small green plants cannot completely absorb all the formaldehyde in a large space.

In any case, in daily life, we should stay away from high concentrations of formaldehyde.

References:

https://ersp.lib.whu.edu.cn/s/org/rsc/pubs/G.https/en/content/articlelanding/2022/gc/d2gc02632e

https://en.wikipedia.org/wiki/Formaldehyde

https://www.piyao.org.cn/2020-09/18/c_1210805932.htm