Atmospheric pollution of a remote area of Tianshan Mountain: Ice core record

[1] The influence of anthropogenic pollution on the region of Tianshan Mountain, a remote area in arid central Asia, has been debated in the recent years. An ice core, covering the past 43 years, retrieved from Glacier 1 at Urumqi River head in the east Tianshan, northwest China, was analyzed to examine the problem. CH3COO- (acetate) and HCOO- (formate), the chief tropospheric carboxylates that can originate from anthropogenic pollution, average 389.4 +/- 336.3 ng g(-1) (N = 489) and 61.1 +/- 89.0 ng g(-1) (N = 541), respectively, with a mean ratio HCOO-/CH3COO- of 0.21 +/- 0.23 (N = 489). SO42-, the major inorganic anion in the core, averages 232.9 +/- 279.9 ng g(-1) (N = 542). The organic and inorganic records have covaried in the past four decades. They originate principally from anthropogenic pollution, coal combustion in particular, of the local and regional atmosphere. The pH values in the record range from 6 to 9 with an average of 6.9 +/- 0.5 (N = 541). The general trend of the pH data matches that of HCOO-, CH3COO-, and SO42-, indicating that the anthropogenic pollution has released considerable particulate material along with unsaturated hydrocarbons and SO2. As a result, the pollution has not been acidifying the environment, but making it alkaline.