Previously, the NIST dual-comb technology was able to detect methane; this upgraded version can sense all primary airborne greenhouse gases – nitrous oxide, carbon dioxide and water vapour – as well as the major air pollutants ozone and carbon monoxide. This new system is suitable for monitoring and understanding emissions of these gases, as well as assessing urban air quality.
A frequency comb is an extremely precise 'ruler' equivalent which allows scientists to measure exact wavelengths of light; each 'tooth' of the comb identifies a different wavelength.
These instruments identify the unique signatures of gases by detecting the amount of light absorbed at each wavelength of the broader spectrum as beams trace a path through the air. Other applications include detecting leaks from oil and gas installations and measuring carbon-intensive emissions from livestock.
Comb systems have an advantage over conventional sensors which sample air...