US EPA

849356 

Journal Article 

Air pollution and meteorological processes in the growing dryland city of Urumqi (Xinjiang, China) 

Mamtimin, B; Meixner, FX 

2011 

1 

Science of the Total Environment
ISSN: 0048-9697
EISSN: 1879-1026 

409 

7 

1277-1290 

English 

21239046 

10.1016/j.scitotenv.2010.12.010 

WOS:000287833600008 

Seven years (2000-2006) of monthly PM(10) (particulate matter, d <= 10 mu m), SO(2), and NO(2) concentrations are reported for Urumqi, the capital of Xinjiang in NW China. Considerably high mean annual concentrations have been observed, which ranged between 150 and 240 mu g m(-3) (PM(10)), 31 and 50 mu g m(-3) (NO(2)), and 49 and 160 mu g m(-3) (SO(2)). The shapes of seasonal variation of all pollutants were remarkably similar: however, winter/summer ratios of concentrations were quite different for PM(10) (2-3) and NO(2) (aroximate to 4) compared to SO(2) (up to 30). Very high consumption rates of fossil fuels for energy generation and domestic heating are mainly responsible for high annual pollution levels, as well as the (very) high winter/summer ratios. Detailed analysis of the 2000-2006 records of Urumqi's meteorological data resulted in inter-annual and seasonal frequency distributions of (a) (surface) inversion events, (b) heights of surface inversions, (c) stability classes of Urumqi's boundary layer, and (d) the "Air Stagnation Index (ASI)". Urumqi's boundary layer is shown to be characterized by high mean annual and seasonal frequencies of (surface) inversions and by the dominance of stable dispersion classes. A further outcome of the meteorological analysis is the proof of Urumqi's strong diurnal wind system, which might have particularly contributed to the stabilization of the nocturnal boundary layer. Annual and seasonal variations of pollutant's concentrations are discussed in the context of occurrences of inversions, boundary layer, stability classes, and ASI. The trend of Urumqi's air pollution indicates a strong increase of mean annual concentrations 2000-2003, followed by a slight increase during 2003-2006. These are in strong contrast to (a) the growth of Urumqi's fleet of motor vehicles and (b) to the growing number of stable regimes of Urumqi's boundary layer climate during same period. It is concluded that the (regional and) local administrative technical countermeasures have efficiently lowered Urumqi's air pollution levels. (C) 2011 Elsevier B.V. All rights reserved. 

Air pollution PM(10) SO(2) NO(2); Annual and seasonal variations; Atmospheric stability classes; Inversion layers; Air Stagnation Index; Mountain-valley breeze