The Picarro G2401 is a high-precision greenhouse gas concentration analyzer that uses Cavity Ring-Down Spectroscopy (CRDS) technology to simultaneously and continuously measure carbon dioxide (CO₂), carbon monoxide (CO), methane (CH₄), and water vapor (H₂O). It offers parts-per-billion (ppb) sensitivity, exceptionally low drift, and long-term stability, meeting the performance requirements of the World Meteorological Organization (WMO) and the Integrated Carbon Observation System (ICOS) for atmospheric monitoring. The analyzer features automatic water correction to report dry gas mole fractions and is suitable for atmospheric science, air quality monitoring, emissions quantification, and climate research. It is designed for both field and laboratory deployment. Sunway Environmental Technology Co., Ltd. is the authorized distributor of Picarro in Hong Kong and Macau, providing equipment supply, technical support, and after-sales services.