A new kind of sensor, researchers suggest, could warn emergency workers when carbon filters into their respirators. This will avoid their inhaling of toxic fumes which have become dangerously saturated.
"The new sensors would provide a more accurate reading of how much material the carbon in the filters has actually absorbed," said team leader Michael Sailor, professor of chemistry and biochemistry and bioengineering at UC San Diego.
"Because these carbon nanofibers have the same chemical properties as the activated charcoal used in respirators, they have a similar ability to absorb organic pollutants, he added.
Sailor's team assembled the nanofibers into repeating structures called photonic crystals that reflect specific wavelengths, or colors, of light.
The sensors are an iridescent color too, rather than black like ordinary carbon. That color changes when the fibers absorb toxins - a visible indication of their capacity for absorbing additional chemicals.
The study was recently published in the journal Advanced Materials.