Asbestos continues to be a health concern in the industrialized world for people working in building remediation, demolition, or a few specialty industries like car breaks manufacturing. Screening environments for the presence of asbestos fibers can help people avoid the cancer-causing mineral mix and identify where breathing apparatuses should be used. Fiber detectors already exist, but they can’t differentiate between asbestos and other materials like fiberglass and gypsum.
Researchers at the University of Hertfordshire in the UK have developed a new sensor that is capable of quickly identifying the presence of asbestos without sending samples to a lab.
Some details of the technology:
When exposed to a magnetic field, asbestos fibers orient themselves to align with the field. The property is virtually unique among fibrous materials. “Asbestos has a complex crystalline structure containing several metals including silicon, magnesium and iron. It is thought that it is the iron atoms that give rise to the magnetic properties, but the exact mechanism is still somewhat unclear,” says Kaye. Kaye notes that his team wasn’t the first to try to exploit the magnetic effect to develop an asbestos detector. “Pioneering U.S.-based scientist Pedro Lilienfeld filed a patent on a related approach in 1988, but it seems it was not taken forward, possibly because of technical difficulties,” he says.
The Hertfordshire team’s new detection method, developed under the European Commission FP7 project ‘ALERT’ (FP7-SME-2008-2), works by first shining a laser beam at a stream of airborne particles. When light bounces off the particles, it scatters to form unique, complex patterns. The pattern “is a bit like a thumbprint for the particle,” says Kaye, sometimes making it possible to identify a particle’s shape, size, structure, and orientation by looking at the scattered light. “We can use this technique of light scattering to detect single airborne fibers that are far too small to be seen with the naked eye,” he says. After identifying the fibers, the detector carries them in an airflow through a magnetic field, and uses light scattering again on the other side to tell if the fibers have aligned with the field. “If they have, they are highly likely to be asbestos,” Kaye says.
The team has tested their detector in the lab and has worked with colleagues in the U.K. and Spain to develop prototypes that are now undergoing field trials at various locations where asbestos removal operations are underway. “Our colleagues estimate that it will take 12 to 18 months to get the first production units for sale, with a target price of perhaps 700-800 U.S. dollars,” Kaye says.
Study in Optics Express: Real-time detection of airborne asbestos by light scattering from magnetically re-aligned fibers…
Press release from the Optical Society: On-site Asbestos Detector Offers Promise of Better Workplace Safety…