Title: ACE-Asia Database_Dunhuang Poly Ions_1.1 This database includes TSP particle-phase concentrations of sulfate, nitrate, and ammonium ions and chloride collected from sampling at the Dunhuang, China (40.20N, 94.48E, Elevation of 1374m) during March 24 to April 4, 2001 as part the ACE-Asia Experiment. The times and dates included in this database are UTC. Please direct any questions about the data to: Rachelle Duvall Water Science and Engineering Laboratory RM 152 660 N. Park Street Madison, WI 53706 (608) 262-4322 (office) (608) 262-0454 (fax) Email Address: rmduvall@students.wisc.edu TSP samples were collected each day for 24-hrs using a High Volume Sampler (Andersen Instruments). Ions and chloride were measured by Ion Chromatography. Columns 1 and 2 contain the start and stop sampling times in UTC for the corresponding sample number. A 10% uncertainty was accounted for due to potential for uneven distribution of particulate matter on the filters during sampling. Rachelle Duvall Last Revised April 2, 2003