Carbon nanotubes are a sort of holy grail of materials science - they can be remarkably strong yet elastic and also make good thermal and electrical conductors. Current and potential applications include use in the manufacture of golf clubs, auto parts, human tissue engineering, electrical components, solar cells, batteries, textiles and perhaps even in far-out concepts from science fiction like space elevators. New research from Rice University finds that this miracle material researchers work countless hours in the lab to create may also be generated in large amount by a far more common source: vehicle exhaust.
Scientists from Rice working with colleagues in France detected carbon nanotubes in cells taken from the airways of French children during normal asthma treatment, which were also found in samples from exhaust pipes of Paris cars and in dust from around the city.
At the heart of the mystery is the process that scientists use in labs to turn carbon monoxide under high pressure into carbon nanotubes. It's at least somewhat similar to the process of turning a car's toxic carbon monoxide emissions into safer exhaust via a catalytic converter, according to Rice chemist Lon Wilson, who is also co-author on a paper in EBioMedicine describing the findings.
"So it is not a big surprise, when you think about it," Wilson said in a release. “It’s kind of ironic. In our laboratory, working with carbon nanotubes, we wear facemasks to prevent exactly what we’re seeing in these samples, yet everyone walking around out there in the world probably has at least a small concentration of carbon nanotubes in their lungs.”
The research doesn't make any definitive conclusions on the potential health impacts of inhaled carbon nanotubes but noted that they do have the potential to cause inflammation in large volumes.
“The concentrations of nanotubes are so low in these samples that it’s hard to believe they would cause asthma, but you never know,” Wilson said. “What surprised me the most was that carbon nanotubes were the major component of the carbonaceous pollution we found in the samples.”
However, the researchers note that the relative "stickiness" and large surface area of nanotubes can make them effective carriers for other pollutants.
