TITLE: Surface Mt. Hallasan, Korea Aerosol Elemental Composition 8-Stage Drum Impactor (Cahill) AUTHORS: Steven S. Cliff The DELTA Group (DAS) 105A Walker Hall University of California Davis, CA 95616 Tel: 530-754-8943 Fax: 530-752-9804 Email: sscliff@ucdavis.edu http://www.delta.ucdavis.edu/ Kevin D. Perry Meteorology Department 135 S 1460 E, Rm 819 University of Utah Salt Lake City, UT 84112-0110 Tel: 801-581-6138 Fax: 801-585-3681 Email: perry@met.utah.edu Thomas A. Cahill The DELTA Group (DAS) 105A Walker Hall University of California Davis, CA 95616 Tel: 530-752-4674 Fax: 530-752-9804 Email: tacahill@ucdavis.edu http://www.delta.ucdavis.edu/ 1.0 DATA SET OVERVIEW: This data set contains size-resolved aerosol elemental composition measurements with 3-hour resolution collected at the Mt. Hallasan site located near the center of Cheju Island, Korea (126.46E, 33.36N, 1100 MSL) from March 30 - April 29, 2001. 2.0 INSTRUMENT DESCRIPTION: Samples were collected on greased mylar substrates using an 8-stage rotating drum impactor operated at a flow rate of 10 lpm. Apiezon (Type L) grease was applied to the substrates in a solution of Toluene to minimize errors associated with particle bounce. The greased mylar substrates were continuously rotated under the slotted orifices at a rate of 2 mm per 12 hours. This instrument physically separates aerosols into eight size classifications based upon their aerodynamic diameters (Table 1). Table 1. Range of Aerodynamic Particle Diameters Collected with the 8-Stage Rotating Drum Impactor. Stage Aerodynamic Diameter Range (micrometers) 1 ~12 - 5.0 2 5.0 - 2.5 3 2.5 - 1.15 4 1.15 - 0.75 5 0.75 - 0.56 6 0.56 - 0.34 7 0.34 - 0.26 8 0.26 - 0.09 Flow through the instrument was controlled by a critical orifice (i.e., stage 8 slotted orifice). Periodic flow audits were conducted to ensure that the critical orifice remained free from obstructions and that the flow remained constant over time. At the completion of the study, the 8-stage Drum impactor was shipped back to the University of California, Davis where the impaction substrates were downloaded in the aerosol sample handling laboratory. 3.0 DATA COLLECTION AND PROCESSING All impaction substrates were analyzed by synchrotron X-ray fluorescence (SXRF) using beamline 10.3.1 at the Advanced Light Source (Lawrence Berkeley National Laboratory). The analysis was performed in a vacuum so all volatile components of the aerosol were removed prior to sampling. Although this technique is capable of quantifying almost all elements from sodium through uranium, in practice, only about 25% of these elements are typically above minimum detectable limits (MDLs) for atmospheric aerosols. Thus, this data set only includes the 19 elements that are routinely above the MDLs for this technique. Other elements can be provided on request, but special care must be taken during interpretation. Deconvolution of the raw X-ray spectra was performed using the QXAS-AXIL X-ray peak-fitting software package which was developed by the IAEA Laboratories in Seibersdorf, Austria. Quantitative analysis of the integrated peak areas was performed by calibrating the response of the system to a series of NIST-traceable standards produced by Micromatter Inc. Impurities in the mylar such as Si, P, Ca, Zn, Ni, and Sb were quantified and found to be negligible. Therefore, no blank subtraction was performed. Corrections were applied to the data to account for matrix effects such as particle size (self absorption) and particle layering. These matrix corrections are most significant for the low energy fluorescence X-rays produced by elements such as Al, Si, and S. The time resolution of the data is 3 hours. 4.0 DATA FORMAT: The data file is a comma-delimited ASCII file. It can be easily opened by Excel using the "comma-delimited" option. DATA VERSION = 1.0 (August 2, 2002), FINAL Parameters include: UTC start date/time (YYYYMMDDHH), UTC stop date/time (YYYYMMDDHH), site longitude (Deg), site latitude (Deg), site altitude (MSL) stage number, Al, Al_err, Si, Si_err, S, S_err, Cl, Cl_err, K, K_err, Ca, Ca_err, Ti, Ti_err, V, V_err, Cr, Cr_err, Mn, Mn_err, Fe, Fe_err, Ni, Ni_err, Cu, Cu_err, Zn, Zn_err, As, As_err, Se, Se_err, Br, Br_err, Rb, Rb_err, Pb, Pb_err. In each case, the error estimate (i.e., _err) describes the uncertainty associated with each measurement. The uncertainty estimate includes factors such as sample volume errors, peak fitting errors, calibration errors, and matrix correction errors. The units for all concentration measurements are nanograms per cubic meter (i.e., ng/m^3) of air at the site elevation. If you want to convert the data to standard temperature and pressure an appropriate correction factor must be applied to the data. 5.0 DATA REMARKS: These data represent elemental concentration measurements only and do not provide direct information regarding the chemical speciation of the elements. The timing errors for this data set are estimated to be +/- 3.0 hours. Data points that are less than three times the uncertainty value should be used with caution. Unavailable data or data that was been removed during the QA process have been reported as -99.999 6.0 REFERENCES Bench, G., P.G. Grant, D. Ueda, S.S. Cliff, K. D. Perry, and T.A. Cahill, The Use of STIM and PESA to Respectively Measure Profiles of Aerosol Mass and Hydrogen Content Across Mylar Rotating Drug Impactor Samples, Aerosol Science & Technology, 36, 642-651, 2002. Cahill, T. A., and P. Wakabayashi, Compositional Analysis of Size-Segregated Aerosol Samples, in Measurement Challenges in Atmospheric Chemistry, American Chemical Society Advances in Chemistry Series No. 232, L. Newman, Ed., pp 211-228, 1993. Perry, K. D., T. A. Cahill, R. C. Schnell, and J. M. Harris, Long-range transport of anthropogenic aerosols to the national Oceanic and Atmospheric Administration baseline station at Mauna Loa Observatory, Hawaii, J. Geophys. Res., 104, 18521-18533, 1999.