Changes in precipitating snow chemistry with seasonality in the remote Laohugou glacier basin, western Qilian Mountains.
Trace elements in the atmosphere could provide information about regional atmospheric pollution. This study presented a whole year of precipitation observation data regarding the concentrations of trace metals (e.g., Cr, Ni, Cu, Mn, Cd, Mo, Pb, Sb, Ti, and Zn), and a TEM-EDX (transmission electron microscope-energy dispersive X-ray spectrometer) analysis from June 2014 to September 2015 at a remote alpine glacier basin in Northwest China, the Laohugou (LHG) basin (4200 m a.s.l.), to determine the regional scale of atmospheric conditions and chemical processing in the free troposphere in the region. The results of the concentrations of trace metals showed that, although the concentrations generally were lower compared with that of surrounding rural areas (and cities), they showed an obviously higher concentration and higher EFs in winter (DJF) and a relatively lower concentration and lower EFs in summer (JJA) and autumn (SON), implying clearly enhanced winter pollution of the regional atmosphere in Northwest China. The TEM observed residue in precipitation that was mainly composed of types of dust, salt-dust, BC-fly ash-soot, and organic particles in precipitation, which also showed remarked seasonal change, showing an especially high ratio of BC-soot-fly ash particles in winter precipitation compared with that of other seasons (while organic particles were higher in the summer), indicating significant increased anthropogenic particles in the winter atmosphere. The source of increased winter anthropogenic pollutants mainly originated from emissions from coal combustion, e.g., the regional winter heating supply for residents and cement factories in urban and rural regions of Northwest China. Moderate Resolution Imaging Spectroradiometer (MODIS) atmospheric optical depth (AOD) also showed a significant influence of regional atmospheric pollutant emissions over the region in winter. In total, this work indicated that the atmospheric environment in western Qilian Mountains also showed enhanced anthropogenic pollution in winter, probably mainly caused by regional fossil fuel combustion.
State Key Laboratory of Cryosphere Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China. dongzhiwen@lzb.ac.cn.
Zhiwen
Z
Dong
State Key Laboratory of Cryosphere Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China.
Dahe
D
Qin
State Key Laboratory of Cryosphere Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China.|Qilian Mountain Glacier and Ecological Environment Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China.
Xiang
X
Qin
Analytical Laboratory of Beijing Research Institute of Uranium Geology, Beijing, 100029, China.
Jianyong
J
Cui
State Key Laboratory of Cryosphere Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China.
Shichang
S
Kang
D000393:Air Pollutants / Q000032:analysis*; D002681:China; D004784:Environmental Monitoring; D046448:Ice Cover / Q000737:chemistry*; D012621:Seasons; D012914:Snow / Q000737:chemistry*
D000393:Air Pollutants
Glacier basin; Precipitation chemistry; TEM-EDX residue; Trace metals