Researchers in France have made a startling discovery. According to a report from Discovery News, the lungs of young patients suffering from asthma were found to be contaminated with man-made carbon nanotubes that were floating in the air.

Carbon nanotubes have many practical industrial applications, particularly in electronics and nanotech. Not all nanotubes are created equally, however – a great deal of nanotubes are produced as a byproduct of catalytic converters in car engines.

Researchers in Paris collaborated with professors at Rice University in Houston to study the nanotubes found inside of the lungs of asthma patients in Paris. The samples weren’t unique to France, however. The same nanotubes were detected in the lungs of patients in Houston, in spider webs in India, and in certain samples of ice taken near the Earth’s poles.

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

The nanotubes discovered in the lung cells of 69 patients between the ages of 2 and 17 were discovered by high-resolution electron microscopes, and were 10 to 60 nanometers in diameter.