Articles | Volume 17, issue 3
Research article
03 Feb 2017
Research article |  | 03 Feb 2017

Dust deposition and ambient PM10 concentration in northwest China: spatial and temporal variability

Xiao-Xiao Zhang, Brenton Sharratt, Xi Chen, Zi-Fa Wang, Lian-You Liu, Yu-Hong Guo, Jie Li, Huan-Sheng Chen, and Wen-Yi Yang

Abstract. Eolian dust transport and deposition are important geophysical processes which influence global bio-geochemical cycles. Currently, reliable deposition data are scarce in central and east Asia. Located at the boundary of central and east Asia, Xinjiang Province of northwestern China has long played a strategic role in cultural and economic trade between Asia and Europe. In this paper, we investigated the spatial distribution and temporal variation in dust deposition and ambient PM10 (particulate matter in aerodynamic diameter  ≤  10 µm) concentration from 2000 to 2013 in Xinjiang Province. This variation was assessed using environmental monitoring records from 14 stations in the province. Over the 14 years, annual average dust deposition across stations in the province ranged from 255.7 to 421.4 t km−2. Annual dust deposition was greater in southern Xinjiang (663.6 t km−2) than northern (147.8 t km−2) and eastern Xinjiang (194.9 t km−2). Annual average PM10 concentration across stations in the province varied from 100 to 196 µg m−3 and was 70, 115 and 239 µg m−3 in northern, eastern and southern Xinjiang, respectively. The highest annual dust deposition (1394.1 t km−2) and ambient PM10 concentration (352 µg m−3) were observed in Hotan, which is located in southern Xinjiang and at the southern boundary of the Taklamakan Desert. Dust deposition was more intense during the spring and summer than other seasons. PM10 was the main air pollutant that significantly influenced regional air quality. Annual average dust deposition increased logarithmically with ambient PM10 concentration (R2 ≥  0.81). While the annual average dust storm frequency remained unchanged from 2000 to 2013, there was a positive relationship between dust storm days and dust deposition and PM10 concentration across stations. This study suggests that sand storms are a major factor affecting the temporal variability and spatial distribution of dust deposition in northwest China.

Short summary
To improve our understanding of the fate and transport of airborne dust, there is a need for long-term records of dust deposition and concentration. This study characterized the spatial and temporal distribution in dust deposition and concentration in central Asia. The occurrence of high dust deposition and concentration suggests this region is a potential contributor to the global dust budget. This work will strengthen our comprehension of aerosol transport in global desertification regions.
Final-revised paper