Aerosol Chemistry Size Distributions for: NAAMES2 - 2016

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VESSEL: R/V Atlantis  DEPARTED: Woods Hole, Massachusetts on 11 May, 2016 ARRIVED: Woods Hole, Massachusetts on 05 June, 2016 Link to more NAAMES2 pages

NOAA PMEL Chemistry Data - collected with 7 stage impactors

Seven-stage multi-jet cascade impactors (Berner et al., 1979) were used to determine the sub- and supermicron concentrations of Cl-, NO3-, SO4=, methanesulfonate (MSA-), Na+, NH4+, K+, Mg+2, and Ca+2. The RH of the sampled air stream was measured a few inches upstream from the impactor. The 50% aerodynamic cutoff diameters, D50,aero, were 0.18, 0.31, 0.55, 1.1, 2.0, 4.1, and 10 um. The RH of the sample air in the impactors was adjusted to 55% RH by controlling the temperature (within feaseable limits) of the impactors.

The impaction stage at the inlet of the impactor was coated with silicone grease to prevent the bounce of larger particles onto the downstream stages. Tedlar films were used as the collection substrate in the impaction stage and a Millipore Fluoropore filter (1.0-um pore size) was used for the backup filter. Films were cleaned in an ultrasonic bath in 10% H2O2 for 30 min, rinsed in distilled, deionized water, and dried in an NH3- and SO2-free glove box. Filters and films were wetted with 1 mL of spectral grade methanol. An additional 5 mLs of distilled deionized water were added to the solution and the substrates were extracted by sonicating for 30 min. The extracts were analyzed by ion chromatography [Quinn et al., 1998]. All handling of the substrates was done in the glove box. Blank levels were determined by loading an impactor with substrates but not drawing any air through it.

Non-sea salt sulfate concentrations were calculated from Na+ concentrations and the ratio of sulfate to sodium in seawater.

Concentrations are reported as ug/m3 at STP (25C and 1 atm).

In the acsii .csv files -8888 indicates Below Detection Limit, and -9999 indicates missing data. The detection limits (DL) vary for each sample because they depend on the amout of air that is filtered for each sample. To get a list of the DLs for each -8888, please contact us.

The 'version zero' set did not include a version number in the file or set name. Version 01 is posted in June, 2017. The only change from version zero to version 01 is that in version zero due to some data processing errors the MSA values were incorrect. The MSA values have been corrected in verison 01. All other ions are unchanged.

Berner et al., Sci. Total Environ., 13, 245 - 261, 1979.
Quinn et al., J. Geophys. Res., 105, 6785 - 6805, 2000.

The data files are available two formats: netCDF and an ascii, csv (comma separated value) format that should load directly into most spreedsheets. The csv file contains header lines that explain that data layout.

Some data files from recent cruises may be password protected. To obtain a password, please contact Jim Johnson or Timothy Bates.

U.S.Dept of Commerce / NOAA / OAR / PMEL / Atmospheric Chemistry