Title: Ship Ron Brown Aerosol Fast (1hr), OC/EC submicron at 55% RH (Turpin) Authors: Barbara J. Turpin (PI) Rutgers University Department of Environmental Sciences 14 College Farm Road New Brunswick, NJ 08901 Phone: 732-932-9540 Fax: 732-932-8644 E-mail: turpin@aesop.rutgers.edu Ho-Jin Lim (operator) Rutgers University Department of Environmental Sciences 14 College Farm Road New Brunswick, NJ 08901 Phone: 732-932-0306 Fax: 732-932-8644 E-mail: hjlim@rci.rutgers.edu 1.0. Data Set Overview 1.1. Introduction: This data set provide semi-continuous PM1.0 organic (OC), elemental (EC), and total carbon (TC) concentrations measured over the Northwest Pacific Ocean and marine environment near East Asia using an automated thermal optical transmittance (TOT) carbon analyzer (Sunset Laboratory, Forest Grove, OR) during the ACE-Asia intensive field campaign. The in-situ carbon analyzer was coupled with an upstream multi-channel parallel-plate carbon impregnated filter (CIF) diffusion denuder to remove gas-phase organic compounds in the sample air. This data set represents PM1.0 OC and EC concentrations of sample air collected at 55% relative humidity. Sampling time for the data set varied from 1 to 8 hrs to reflect the large variations in atmospheric carbonaceous aerosol concentrations over the study region. 1.2. Time period covered by the data: March 14 û April 20, 2001 1.3. Platform: R/V Ronald H. Brown 2.0. Instrument Description The TOT in-situ carbon analyzer is the commercial version of the instrument described by Turpin et al. [1990] and utilized in three previous field studies [Turpin et al., 1990; Turpin and Huntzicker, 1995; Lim et al., 2001]. Particles in the sample air were collected on a quartz fiber filter (ca. 1.5 square cm, QAT-UP, PallGelman, Ann Arbor, MI) mounted inside the semi-continuous carbon analyzer at 7.8 L/min and analyzed automatically by TOT immediately after collection. Turpin et al. [1990] and Birch and Cary [1996] describe the TOT OC and EC analysis method in detail. The ACE-Asia temperature protocol similar to NIOSH protocol, also being used by U.S. EPA, was used. Briefly, air is purged from the analyzer after sample collection. The quartz fiber filter is then heated in a helium environment, stepwise, to 870 degree-C to volatilize OC. EC is eluted by combustion in 10% oxygen in helium, heating stepwise to 880 degree-C. A calibration gas with a known amount of methane (17.0 microgram of carbon) is automatically injected in the last step of the analysis for quantitation. The transmittance of light through the quartz fiber filter is monitored using a diode laser and a photodetector to correct the pyrolysis of OC to EC during analysis. During heating in an oxygen-free environment, some of the organic carbon pyrolyzes, reducing the transmittance through the filter. The amount of carbon that has been pyrolytically converted to EC is considered to be the amount of EC that must be removed to return the transmittance to its pre-pyrolysis value. Thus, the OC-EC split occurs when the transmittance returns to its pre-pyrolysis level. Ultra high purity helium, 10% oxygen in helium, and 2.09% methane in helium (certified grade), ultra high purity hydrogen, and zero grade air were used for semi-continuous carbon analysis. Pressurized gases from Praxair were used without further purification except that the helium passed through a series of gas purifiers (4002; 4004; Alltech, Deerfield, IL) to remove trace amounts of oxygen prior to use. A color indicator in the second gas purifier was monitored to check for oxygen breakthrough; it showed no color change during the study. The carbon analyzer was located in a NOAA container in the forward section of the ship. Sample air was drawn through a common sampling manifold used to reduce discrepancies in measurement data caused by different sampling conditions. Thirty L/min of this flow was pulled through a 1ö stainless steel tube, a 1 micron-diameter cutpoint impactor, and about 4 m of 3/8ö copper tubing, into a plenum. In the plenum, the flow was split between the semi-continuous carbon analyzer (7.8 L/min) and 2 auxiliary filter holders (11.2 L/min). The measurement system was connected to the NOAA-PMEL vacuum system, which closed a valve to prevent sampling when the sampling manifold was impacted by the shipÆs stack emissions. When evidence of contamination such as atypical increase of particle number concentrations is observed, a signal was generated to turn off the solenoid valve downstream of the carbon analyzer and auxiliary filters until the particle concentration returned to typical values. 3.0. Data collection and processing 3.1. Quality control 3.1.1. Instrument blanks: instrument blanks were measured to monitor the contamination of instrument. 3.1.2. FID response factor: instrument sensitivities in OC and EC portions of the analysis relative to the instrument sensitivity for the calibration peak were measured. 3.1.3. Calibration loop volume: ratio of actual carbon mass to measured carbon mass were measured. 3.1.4. Dynamic blanks: dynamic blanks were run by placing a Teflon filter upstream of the denuder and carbon analyzer to remove particles. This provides an estimate of adsorption of organic vapor on the sampling filter. 3.2. Quality assurance Integrated filter samples were collected concurrently in two ports as a quality assurance. One port contained a 47 mm quartz fiber filter (QAT-UP, PallGelman, Ann Arbor, MI). The other contained a 47 mm Teflon (Teflo 2 micron, PallGelman, Ann Arbor, MI) followed by a 47 mm quartz fiber filter (QAT-UP, PallGelman, Ann Arbor, MI). This two-port system is a typical approach to the measurement of 24-hr average particulate carbon concentrations [Turpin et al., 2000]. OC on the backup filter (i.e., the quartz fiber filter behind the Teflon filter) is exposed to particle-free ambient air and provides an estimate of adsorption of organic gases on the quartz fiber front filter. The backup filter is subtracted from the concurrently-collected quartz fiber front filter to report particulate OC and EC. Auxiliary sample filters were changed every 24 hrs, with some exceptions to accommodate the broader study sampling schedule and changing ambient conditions. All quartz fiber filters used in the study were cleaned in a muffle furnace at 550 degree-C for greater than 2 hrs. Sampling-port flow rates were maintained at 11.1, and 11.1 L/min for auxiliary quartz and Teflon-quartz filter ports, respectively. OC and EC of filter samples were analyzed using a TOT laboratory carbon analyzer (Sunset Laboratory, Beaverton, OR) with ACE-Asia temperature protocol. 3.3. Calculation of ambient OC and EC concentrations Ambient OC and EC concentrations were calculated by dividing net OC and EC mass of samples by the corresponding sample air volume. Net OC and EC mass is defined as OC and EC mass of samples minus dynamic blank estimates of OC and EC at the corresponding sample air volume. 4.0. Data format 4.1. Data file structure: column delimited ASCII 4.2. Data format and layout: header records in the data file describe general information about semi-continuous OC-EC measurements and data records. Those are followed by parameter labels and units, and data including OC and EC concentrations. 4.3. List of parameters Sdate: sampling start date (UTC) Stime: sampling start time (UTC) Edate: sampling end date (UTC) Etime: sampling end time (UTC) Lat: averaged latitude for the corresponding sampling time (degree) Longt: averaged longitude during the corresponding sampling time (degree) OC: organic carbon (ug/m3: microgram/cubic meter) OCflag: comment on the corresponding OC data EC: elemental carbon (ug/m3: microgram/cubic meter) ECflag: comment on the corresponding EC data TC: total carbon (OC + EC; ug/m3: microgram/cubic meter) TCflag: comment on the corresponding TC data 4.4. Description of flags Flags Definitions -999 Missing data 3PCAL 3 peak calibration of FID response factors - QC BDL Below detection limit - invalid DBLNK Dynamic blank - QC FOP Filter out of position - valid (flagged in necessary) IBLNK Instrument blank - QC IPAR Invalid analysis parameter LFID Low FID signal - valid, higher uncertainty LOOP Loop volume check - QC LSV Low sample volume - valid (flagged if BDL) NPC No pump control - suspect, possible ship stack influence OFID FID off - invalid SPLIT Bad OC-EC split - TC valid, OC and EC invalid ZMC Zero minute collection - instrument blank 4.5. Data version: Version 1.0 (January 23, 2002) 5.0. Data remarks Any questions or comments regarding this data set should be addressed to the authors listed at the top of this document. 6.0. References Birch, M.E. and R.A. Cary, Elemental carbon-based method for monitoring occupational exposures to particulate diesel exhaust, Aerosol Sci. Technol., 25, 221-241, 1996. Lim, H.-J., B.J. Turpin, E. Edgerton, S.V. Hering, G. Allen, H. Maring, and P. Solomon, Semi-continuous aerosol carbon measurements: Comparison of Atlanta Supersite Measurements, J. Geophys. Res., submitted, 2001. Turpin, B.J., R.A. Cary, and J.J. Huntzicker, An in situ, time-resolved analyzer for aerosol organic and elemental carbon., Aerosol Sci. Technol., 12, 161-171, 1990. Turpin, B.J. and J.J. Huntzicker, Identification of secondary organic aerosol episodes and quantification of primary and secondary organic aerosol concentration during SCAQS, Atmos. Environ., 29, 3527-3544, 1995. Turpin, B.J., P. Saxena, and E. Andrews, Measuring and simulating particulate organics in the atmosphere: Problems and prospects, Atmos. Environ., 34, 2983-3013, 2000.