Even as the pace of nanotechnology research accelerates in labs around the world, a few early studies have raised concerns that tiny man-made particles might pose threats to human health or the environment. While the extraordinary properties of nanoparticles (those smaller than 100 nanometers, the size scale of viruses and even individual molecules) could enable everything from extremely sensitive diagnostic tools to superstrong materials, those same properties might also allow them to penetrate deeper into the lungs, pass more readily through skin, or linger longer in the environment as pollutants-effects that could trigger new regulations.

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