Abstract: The increasing volume fraction of CO2 in the atmosphere has led to the intensification of global warming, and at the same time, plasces higher demands on high-precision detection of CO2 and accurate monitoring and assessment of its emissions. In response to this requirement, a measurement system based on Fabry-Perot interferometer was developed for atmospheric CO2 measurement in this paper. The system was calibrated using sample gas in the laboratory, and it was found that the relative error of the system measurement was less than 0.5%, the detection accuracy was better than 1.43 × 10-6, and the system detection limit was 1.24 × 10-6 at a time resolution of 30 minutes. To further verify the feasibility of the system for measurement in actual atmospheric environments, a comparison test between this system and a portable FTIR spectrometer for measring atmospheric CO2 volume fraction was carried out outdoors for 14 days. The results showed that the CO2 volume fraction measured by the two systems exhibited consistent trends with a correlation coefficient R2 of 0.81, indicating that the system can provide a portable and highaccuracy reference solution for online monitoring of atmospheric CO2 volume fraction.

Key words: Fabry-Perot interferometer, absorption spectroscopy, carbon dioxide, portable measurement