New progress in the study of stable isotope of atmospheric particulate mercury

[ Instrument Network Instrument Development ] Atmospheric particulate mercury may be affected by complex gas-particle distribution and chemical conversion processes during transportation, resulting in isotope fractionation and changing of the original isotope characteristics, making it more difficult to directly trace the source using mercury isotope. .

New progress in the study of stable isotope of atmospheric particulate mercury

Considering the possible diurnal photochemical process differences of atmospheric particulate mercury, Dr. Huang Qiang of the Institute of Geochemistry, Chinese Academy of Sciences, Chen Qiang, studied the diurnal variation of the isotope composition of atmospheric particulate mercury in Beijing using mercury stable isotope. By quantitative analysis of mercury isotope composition of 昼 and night PM2.5 samples, it is found that the isotope composition of particulate mercury, especially non-mass fractionation has significant diurnal variation (as shown on the right), non-quality of daytime samples (day) Fractionation Δ199Hg is significantly higher than nighttime (night). Through the geochemical characteristics of the sample and the air mass trajectory model analysis, the results show that this diurnal variation is not caused by changes in source contribution, but more likely due to photochemical reduction of divalent mercury on the particles. The results of this study show that, besides the general change of temperature difference between day and night caused by the change of temperature difference between day and night, the photochemical reduction process of atmospheric particulate mercury can also lead to the diurnal variation of the mass concentration of particulate mercury. The gaseous elemental mercury may also be a contributing end element of gaseous elemental mercury in the atmosphere. The conversion process of particulate mercury and gaseous mercury remains to be further studied.

The project was funded by the National Natural Science Foundation of China and the key research and development plan of the Ministry of Science and Technology. Related results have been published in Atmospheric Chemistry and Physics.

(Original title: New progress in the study of stable isotope of atmospheric particulate mercury)