Scientists were shocked to discover carbon nanotubes from cars in human lungs cells.

Lung samples from Parisian children undergoing asthma treatment revealed the puzzling presence of man-made carbon nanotubes, and later researchers discovered the same material in the exhaust pipes of Paris vehicles, Rice University reported. The researchers noted the findings do not directly link carbon nanotube inhalation to asthma, but suggest humans are exposed to these materials on a daily basis. Carbon nanotubes can be produced naturally through volcanic activity and other types of combustion, but a car's catalytic converter (which converts carbon monoxide into safer emissions) closely resembles systems used to create carbon nanotubes.

To make their finding, the researchers looked at cells taken from 69 randomly selected asthma patients between the ages of 2 and 17 who underwent routine fiber-optic bronchoscopies as part of their treatment. The team found carbon nanotubes in all of the samples.

"The concentrations of nanotubes are so low in these samples that it's hard to believe they would cause asthma, but you never know," said Rice chemist Lon Wilson. "What surprised me the most was that carbon nanotubes were the major component of the carbonaceous pollution we found in the samples."

The team used Raman spectroscopy to analyze the cell samples, samples from the exhaust pipes of cars in Paris, and from busy and non-busy intersections. The nanotubes were also found in these environmental samples.

"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," Wilson said.

The findings were published in a recent edition of the journal EBioMedicine.