August 13, 2010
Column | Korky Koroluk
Nanotechology has rewards, risks
Nanotechnology, the science of the incredibly small, is the subject of so much research that it’s impossible to keep up with it all. Its potential for immense advancements in medicine get the most publicity, but after that, the best bet for possible positive impacts occur in the construction industry.
We’ve already seen examples of nanomaterials that can strengthen both steel and concrete, keep dirt from sticking to windows, make materials fire-resistant, greatly improve the efficiency of solar panels, boost the efficiency and even allow bridges and buildings to “feel” the cracks, corrosion and stress that will eventually cause structural failures.
Now , Pedro Alvarez and a research team at Rice University in Houston have done a review of existing research. In the process they found enough work already done to confirm the notion that “the advantages of using nanomaterials in construction are enormous.”
The team concluded that since 41 per cent of all energy use in the United States is consumed by commercial and residential buildings, “the potential benefits of energy-savings materials alone are vast.”
They said in a recent paper that the materials can be used in insulating ceramics and paints or other coatings to improve thermal performance. Their use could improve energy transmission, lighting and/or heating devices. They can also be used to enhance energy storage systems such as batteries and capacitors.
They can extend the durability of structures through improved resistance to corrosion, fatigue, wear and abrasion. This in turn will lead to savings in the energy that would otherwise be used during repair or replacement.
The paper, in fact, was a ringing endorsement of the use of nanomaterials — but there is a downside.
Nanomaterials can pose hazards, they noted, adding that concerns about unintended consequences are reasonable and must be addressed.
“The time for responsible life-cycle engineering of man-made nanomaterials in the construction industry is now, before they are introduced in environmentally relevant concentrations. “
Risk factors, they wrote, include occupational exposure of workers during coating, moulding, compounding and incorporation of nanomaterials into the finished building materials or components. As well, there is a possible hazard from wider exposure of the surrounding community during construction, repair, renovation and, especially, demolition. They worried that at the end of the lifecycle there is a risk to the environment as the nanomaterials are disposed of.
The uncertainty arises because the very idea of nanomaterials is still in its infancy. Their manufacture involves engineering substances at the molecular level, something that was unthinkable just a generation ago.
When materials are made into nanoparticles, the ratio of their surface area to volume increases. The greater surface area may lead to increased absorption through the skin, lungs or digestive tract and may cause unwanted effects to the lungs and other organs.
The exact nature and size of the risk is something that is still not understood, so studies are essential, the authors say. What is already known is that some nanoparticles (zinc oxide or titanium dioxide, for example) can cause low-level DNA damage. The worst found so far is copper oxide, the only nanomaterial yet identified as a clear health risk.
The authors are careful not to warn people away from nanotechnology — the advantages, both known and anticipated, are too great for that.
But they do urge caution. “Whether nanoenabled construction materials could be designed to be “safe” and still display the properties that make them useful is an outstanding question.”
Korky Koroluk is an Ottawa-based freelance writer. Send comments to email@example.com
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