Cleaner Air Through Better Finishing?

One of the potentially exciting developments in wood flooring is a new twist on an old technology—a chemical reaction by additives in wood finishes that might actually remove VOC’s from a room’s air. Sounds too good to be true? Unfortunately it might just be…at least for now.

The basis for the tech is old fashioned chemistry, a simple chemical reaction, which as you will remember from high school is “a process that leads to the transformation of one set of chemical substances to another.”

In this case, you start with a chemical known as titanium dioxide (TiO₂). TiO₂ reacts to UV light (sunlight) which can then cause a further reaction with certain chemicals like formaldehyde from the surrounding air, breaking them into component parts. HCHO, better known as formaldehyde, is ultimately broken into carbon dioxide (CO₂) and water (H₂O). Many other air borne chemicals may also respond to the original reaction.

The chemistry process is well known—it’s been studied in Japan for decades. It’s been utilized in air conditioning units, paint, concrete and a variety of other building products. But the jury is still out regarding the real effectiveness, and in certain applications, it may actually do more harm than good.

I’ve only seen marketing material and anecdotal stories, not the actual research studies done by companies advertising these finishes, but I did talk to some scientists about the process itself and researched public reports to find out what others have done.

Most research has been on larger air conditioning units and concrete applications, and I was told that without seeing the very exact testing protocols used to substantiate claims regarding wood flooring finishes, no one could give a real opinion. I was told designing a meaningful test would be “challenging to say the least.” I was also advised that the variables involved in the real world were too numerous to begin to quantify, but the list included the presence of throw rugs or furniture, window location, air circulation in the home, general environmental humidity, dirt, etc.

It was also suggested to me that while the science was feasible, it was likely that the amount of UV required to make this a truly effective product in an interior finish or paint would exceed safe radiation limits. I was told that I wouldn’t just get a severe sunburn, but would be advised to take a radiometer reading before entering the room!

More formal studies suggest that effectiveness really does seem to be the big question. Researchers looking at the use of this type of system in active air conditioning systems at the Lawrence Berkeley National Laboratory reported that “Photocatalytic Oxidation (PCO) reduces indoor VOC’s but could produce formaldehyde as a byproduct.“ They reported that

“theoretically all VOC’s will be broken down into carbon dioxide and water. However, in many cases the reactions to receive this end state have numerous stages, can be complex and can produce relatively stable intermediary byproducts. The question is whether or not the Photocatalytic Oxidation process can react quickly enough and completely enough with VOC’s to neutralize them and not create harmful VOC’s as unintended byproducts.”

I also found a good summary of the science behind these types of treatments which pointed out some the following concerns:

  • Limited exposed surface area means limited effectiveness
  • Humidity inhibits the reaction rate so where you live can make a difference
  • Inorganic contamination (also known as dirt) deactivates the catalyst
  • Incomplete oxidation results in ~4 times higher levels of formaldehyde and acetaldehyde

And the State of California, our favorite source for these types of studies, offered the following conclusion in one older general research paper:

“Photocatalytic reduction of air pollution using titanium dioxide nanoparticles is technically feasible. However, accomplishing this goal in a cost‐effective way will be challenging, due to the large volumes of air that must be processed….Before implementation, additional research should be conducted to ensure that deployment of the photocatalyst does not lead to any adverse environmental consequences—such as the release of harmful compounds into the atmosphere or water (runoff).”

So I think the jury is still out. It’s a promising technology, but I don’t know if it’s really effective in a meaningful way in real life, at least in most applications of interior flooring. I love the idea of pushing the boundaries, of the application of technology and science to better our lives. I just want to see the data and know that I’m not paying for “a difference that makes no difference” or worse, something which is reducing one possible negative by creating another.

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