Differential absorption lidar system employed for background atomic mercury vertical profiling in South China

•A new differential absorption lidar system with a Nd:YAG pumped dye laser transmitter is described.•The system performance was verified by detailed measurements on multiple UV absorption lines from atmospheric molecular oxygen.•The intended use of the system for sensitive measurements of atmospheric atomic mercury was demonstrated in a 24 hour vertical concentration measurement session in a major city in Southern China.

A differential absorption lidar (DIAL) system based on a Nd:YAG laser pumped narrow-band dye laser is developed and employed to monitor the atmospheric background concentration of atomic mercury in Guangzhou, South China. Atmospheric oxygen is also studied by using neighboring wavelengths to the mercury absorption line (253.7 nm), and is used to verify the operation of the DIAL system. A 24-hour continuous monitoring of background mercury concentration is performed and the average atomic mercury concentration below 330 m is between 5 ng/m3 and 12 ng/m3.