Nanotechnology and Coatings
In helping our clients choose healthy building materials, I tend to be weary of coatings in general, but nanocoatings are of particular concern. In building materials, manufacturers advertise nanocoatings on carpets, upholstery, photovoltaics, and even toilets. I’ve seen these coatings used as stain repellants, waterproofing coatings or as finishes that create a smooth and easily cleaned surface. Are green nanotechnology and coatings available?
Despite the advantages of using nanotechnology in building materials, we at Healthy Building Science have approached this technology cautiously. EPA and environmental groups have raised concerns about its use in consumer products, and BuildingGreen has highlighted similar problems in the building industry.
Nanotechnology deals with materials between 1 and 100 nanometers, with a nanometer (nm) being one billionth of a meter. The concern with nanotechnology is that nanoparticles are so tiny that once they are inhaled or ingested, they bridge the blood-brain barrier uninhibited. This increased absorption of a particular nano-material may be desirable for some medical therapies, but it is not a good thing when you are dealing with chemicals known to be toxic to living organisms.
For example, highly fluorinated chemicals are being used to coat building materials to give them water and stain repellant properties, and we know many of these chemicals are persistant, bioaccumulative, and toxic. We also know that what we put in our buildings ends up in our bodies. So what happens when these toxic nanoparticles end up in our bodies? Are factory workers and installers experiencing greater exposures to these chemicals? And how are these nanoparticles being disposed of? Are they ending up in our environment?
Nanotechnology in Toilets?
Some manufacturers are offering nanocoatings on their toilets to reduce dirt accumulation and scaling. The intention may be good: reduce the use of toxic cleaners by decreasing the need for cleaning. But when manufacturers employ a nanocoating to achieve this end, are we just replacing one toxic input with another?
The good news is that not all coatings are created equal. When I was asked to review TOTO toilets with Sanagloss coating, as usual, I was skeptical that the coating was made of nontoxic materials. The contractor put me in touch with TOTO, and I outlined my concerns: Was the coating a nanocoating? Was it fluorocarbon-based?
Fortunately, the answer to both questions was “No.” TOTO’s Sanagloss is neither a nanocoating nor a fluorochemical. Instead, it is a special ceramic glaze that is fired at extremely high temperatures to achieve an especially smooth surface that resists staining.
While I would still recommend being weary of specialty coatings in building products, always ask before jumping to conclusions! In so doing, we often find manufacturers that are considering human health alongside product improvements. With some due diligence, green nanotechnology and coatings can be found.