Laser spectrometer precisely monitors atmospheric N2O and CO

Nitrous oxide (N₂O) and carbon monoxide (CO) are important drivers in global warming. However, there are many difficulties in reliable monitoring, especially for N₂O, as the concentration of N₂O in atmospheric is only a few hundred parts per billion. However, the compatibility precision recommended by World Meteorological Organization (WMO) is much lower. Therefore, a solution that can offer more precise monitoring is needed.

Researchers led by Prof. Gao Xiaoming from the Hefei Institutes of Physical Science (HFIPS) of the Chinese Academy of Sciences developed a dual gas sensor with high precision and low drift to measure atmospheric N₂O and CO. Related findings were published in Sensors and Actuators B: Chemical.

The researchers designed an improved White Cell to obtain long optical path length (76 m) at a short base length (34.5 cm). The radio frequency noise was equipped to low optical fringes. Combined with an Interband Cascade Laser, they got a high precision spectrometer for atmospheric greenhouse gases N₂O and CO.

With this spectrometer, the researchers can test micro-daily-drift (less than 1.5 part per trillion). The precisions of N₂O and CO reached 0.065 part per billion and 0.133 part per billion, respectively, which meets the requirement of WMO.

This work provides a potentially valuable laser spectrometer for highly precise measurement of greenhouse gases, which is of great significance to the monitoring and suppression of global warming.