Lanzhou was one of the most air-polluted cities in China over the past few decades due to its narrow river valley topography and industrial emissions. In the past decade, with the implementation of corresponding air pollution control measures, Lanzhou’s air quality has largely improved. 

However, research on atmospheric mercury is still lacking in cities in northwest China. Therefore, it is necessary to update the understanding of atmospheric mercury in Lanzhou and northwest China. 

Recently, a research group led by Prof. KANG Shichang from the Northwest Institute of Eco-Environment and Resources of the Chinese Academy of Sciences, together with scholars from domestic and foreign research institutes and universities, carried out one year of online total gaseous mercury (TGM) measurements for the first time in Lanzhou. 

Scientists conducted continuous measurements of high-time resolution TGM for the first time in Lanzhou, and used meteorological and air quality data, principal component analysis, conditional probability function, backward trajectories and concentration weighted trajectory to identify the temporal variation, long-range transport impacts and potential sources of TGM in Lanzhou. 

In addition, they also conducted a brief synthesis of multi-decadal changes in atmospheric mercury in China's mega cities and the potential linkage to mercury pollution control. 

This study has been published on the Science of the Total Environment in an article entitled "Latest observations of total gaseous mercury in a megacity (Lanzhou) in northwest China".