http://bolin.su.se/data/oden-ao-2018-ultrafine-aerosol-composition-2 Michael Lawler Bolin Centre Database 2021 Datafile Atmosphere Aerosols Aerosol chemical properties Aerosol composition Ultrafine aerosol Nanoparticles TDCIMS High Artic North Pole Arctic Ocean AO2018 MOCCHA Icebreaker Oden Earth science > Atmosphere > Aerosols Michael Lawler 2021-11-02T21:40:51+00:00 English 2 The data are provided in six comma-separated values (csv) files, and in six corresponding xlsx spreadsheet files, with the following content: ##### Mass fractions Mass fractions are reported on the basis of calibrated amounts of different compounds relative to the total collected aerosol mass measured by scanning mobility particle sizing (SMPS) downstream of the particle collection wire, assuming particle phase density of 1.7 g/cm³. Only collections with greater than 0.01 ng of collected mass and where no contamination from ship stack was found have reported values. Individual species below detection limits also are not reported. However all times of Aitken mode collections are shown for completeness. Each ionization mode has its own file (positive and negative). ##### Atmospheric concentration estimates The mass fraction data are further extended to estimate the total ambient mass concentrations of the calibrated species in the Aitken mode, here defined as particles < 70 nm mobility diameter. The fractions were applied to the total aerosol mass below 70 nm to achieve this, based on the University of Stockholm ACES differential mobility particle sizer (DMPS) ambient number concentrations, assuming 1.7 g/cm³ particle density. Collections with collected masses > 0.01 ng are reported here. Only points for which an automated algorithm identified a clear peak in the background-corrected data are included. This includes points below the detection limit and even some negative values (background signal > collection signal). Two files for each polarity are included, one in units of pmol/m³ (_pmolm3 in filename) and one in units of ng/m³ (_ngm3 in filename). Explanation of column headers in the csv files: ##### Reported metadata * start_collection and end_collection: timestamps bookending the present sample collection * Latitude: mean latitude of Oden during collection * Longitude: mean longitude of Oden during collection * coll_mass: estimated mass collected on filament * VMedD: volume median mobility diameter of collected particles * Dp_min: below this diameter particles contributed less than 5% of the collected mass * Dp_max: above this diameter particles contributed less than 5% of the collected mass ##### Reported negative ion data * Sulfate: SO₄²⁻ * IO3: iodic acid (assuming I⁻ detected is primarily from this species) * MSA: methanesulfonic acid * Cl: chloride ##### Reported positive ion data * Ammon: ammonium (NH₄⁺) * DMA: dimethylammonium (C₂H₈N⁺) * polysacch: polysaccharide (assuming C₆H₁₀O₅ monomer mass) * SOA: secondary organic aerosol- not a calibrated species, only an estimate; no molar concentration estimate * Potassium: potassium (K⁺), likely an underestimate due to poor sensitivity to potassium sulfates * TMA: trimethylammonium (C₃H₁₀N⁺) MA: methylammonium (CH₆N⁺) Sodium: Na⁺ ##### Error estimate * _err: standard error of the corresponding value (based on ion counting statistics) Note that positive ion data begin on 9. August 2021, later than the negative ion data. This is because a change was made to the positive ion transmission settings on 8. August and the various sensitivities were likely different during that early period. Please contact Michael Lawler if data are being used for any research project or publication. Data were collected during the Arctic Ocean 2018 expedition on board the Swedish icebreaker (I/B) Oden, which was organized by the [Swedish Polar Research Secretariat](https://polarforskningsportalen.se/en/arctic/expeditions/arctic-ocean-2018). #### Version history ##### Version 2 Updated mass fractions data, including more points (data for > 0.01 ng collected mass, instead of > 0.025 ng). ##### Version 1 Initial release.