Single-particle measurements of fluorescent bioaerosols and other coarse particles during the Arctic Ocean 2018 expedition

Julia Kojoj, Gabriel Pereira Freitas, Paul Zieger

Using a single-particle online optical instrument we measured the coarse particle concentration (optical diameter bigger than 0.8 µm) on the 4th deck of icebreaker Oden during August and September 2018, along the track of the Arctic Ocean 2018 expedition. Using ultra-violet laser-induced fluorescence detected in 8 channels, we further categorised these particles into non-fluorescent, fluorescent, highly-fluorescent and fluorescent primary biological aerosol particles (fPBAP). fPBAP accounts for particles such as bacteria and fungal spores.

We provide single-particle data for each particle category, including the fluorescence in each of the 8 channels, particle size, morphology, and particle group, which indicates in which channels the fluorescence exceeds 9 sigma above the background.

fPBAP are known to be efficient ice nucleating particles (INP), which facilitate the growth of ice particles in the atmosphere. This dataset thus provides insights on the relationship between PBAP and INP in the Arctic and a valuable source for parameterization of high-temperature Arctic INP.

Citation

Julia Kojoj, Gabriel Pereira Freitas, Paul Zieger (2024) Single-particle measurements of fluorescent bioaerosols and other coarse particles during the Arctic Ocean 2018 expedition. Dataset version 1. Bolin Centre Database. https://doi.org/10.17043/oden-ao-2018-aerosol-mbs-1

References

Kojoj J, Freitas GP, Muilwijk M, Granskog MA, Naakka T, Ekman AML, Heutte B, Schmale J, Da Silva A, Lapere R, Marelle L, Thomas JL, Melsheimer C, Murray BJ, Zieger P (2024) An Arctic Marine Source of Fluorescent Primary Biological Aerosol Particles During the Transition from Summer to Autumn at the North Pole. Tellus B: Chemical and Physical Meteorology 76(1):1–24. https://doi.org/10.16993/tellusb.1880

Karlsson L, Baccarini A, Duplessis P, Baumgardner D, Brooks IM, Chang RY‐W., Dada L, Dällenbach KR, Heikkinen L, Krejci R, Leaitch WR, Leck C, Partridge DG, Salter ME, Wernli H, Wheeler MJ, Schmale J, Zieger P (2022) Physical and Chemical Properties of Cloud Droplet Residuals and Aerosol Particles During the Arctic Ocean 2018 Expedition. Journal of Geophysical Research: Atmospheres 127. https://doi.org/10.1029/2021jd036383

Freitas GP, Stolle C, Kaye PH, Stanley W, Herlemann DPR, Salter ME, Zieger P (2022) Emission of primary bioaerosol particles from Baltic seawater. Environmental Science: Atmospheres 2:1170–1182. https://doi.org/10.1039/d2ea00047d

Ruske S, Topping DO, Foot VE, Kaye PH, Stanley WR, Crawford I, Morse AP, Gallagher MW (2017) Evaluation of machine learning algorithms for classification of primary biological aerosol using a new UV-LIF spectrometer. Atmospheric Measurement Techniques 10:695–708. https://doi.org/10.5194/amt-10-695-2017

Data description

All data provided was obtainded using a multiparameter bioaerosol spectrometer (MBS). Details on the instrument can be found in Ruske et al. (2017).

The data are provided in two different ways:

• mean 3-hourly concentrations of each particle type
• single-particle data for each particle type

The four particle types are:

• coarse particles
  • all detected particles
• fluorescent particles
  • fluorescence at least 3 sigma above the background
• fluorescent primary biological aerosol particles (fPBAP)
  • highest fluorescence in the second channel, at least 9 sigma above the background
• other highly fluorescent particles
  • fluorescence at least 9 sigma above the background, in any channel

The classification follows the method outlined by Freitas et al. (2022), and is also described in Kojoj et al (2024).

Mean 3-hourly concentrations

mbs_concentrations.csv has the following columns:

• time Date and time (UTC). Format: yyyy-mm-dd HH:MM:SS
• Coarse 3-hour mean concentration of coarse particles (particles/liter)
• Coarse_no_pollution 3-hour mean concentration of coarse particles (particles/liter), with polluted periods removed using pollution mask from Karlsson et al. (2022).
• FP 3-hour mean concentration of fluorescent particles (particles/liter)
• OHFP 3-hour mean concentration of other highly fluorescent fluorescent particles (particles/liter)
• fPBAP 3-hour mean concentration of fPBAP (particles/liter)

Single-particle data

The single-particle data is given in one comma separated values file per particle type:

• coarse_single_particle.csv
• fp_single_particle.csv
• fpbap_single_particle.csv
• ohfp_single_particle.csv

Each file contains information such as size, morphological parameters and spectral grouping.

coarse_single_particle.csv does not contain fluorescence intensity, since not all particles are fluorescent, but the rest of the files contain a column for each of the 8 fluorescence channels.

For fp_single_particle.csv and ohfp_single_particle.csv, a column is included to indicate if the detector was saturated in one or more of the fluorescence channels. For fpbap_single_particle.csv, no saturating particles are included.

All single-particle files have the following columns:

• time Date and time (UTC) of detection of the particle. Format: yyyy-mm-dd HH:MM:SS
• Size Particle diameter (micrometers)
• AsymLR% Particle asymmetry, estimated by the summed differences between scattering data measured by the left and right mirror arrays. Percentage value where 0% represent a perfect sphere.
• PeakMeanR The peak pixel vallue in the array scattering data for the partciel, divided by the mean pixel value. A unitless ratio, higher numbers can indicate elongated particles.
• MeanR Mean pixel value in the right linear detector array, arbitrary unit (a.u.)
• Total Number of particles/s that are detected, whether or not further data is measured for them.
• Measured Number of particles/s that are detected, and have all measurements recorded.
• count Particle count for the fiven particle, should be 1.

fpbap_single_particle.csv, ohfp_single_particle.csv, and fp_single_particle.csv also contain the following columns:

• XE1_1 Fluorescence recorded in channel 1, centred around 315 nm, a.u.
• XE1_2 Fluorescence recorded in channel 1, centred around 364 nm, a.u.
• XE1_3 Fluorescence recorded in channel 1, centred around 414 nm, a.u.
• XE1_4 Fluorescence recorded in channel 1, centred around 461 nm, a.u.
• XE1_5 Fluorescence recorded in channel 1, centred around 508 nm, a.u.
• XE1_6 Fluorescence recorded in channel 1, centred around 552 nm, a.u.
• XE1_7 Fluorescence recorded in channel 1, centred around 595 nm, a.u.
• XE1_8 Fluorescence recorded in channel 1, centred around 640 nm, a.u.
• Group Letter combination of all channels where the particle's fluorescence exceeds 9 sigma above the background, in order of fluorescence intensity. A corresponds to the first channel, B to the second, and so on. As an example, particles in group BCE have fluorescence peaks more than 9 sigma higher than the background in the second, third, and fifth channel, with highest flourescence in channel B, then C, then E.

ohfp_single_particle.csv and fp_single_particle.csv also contain the column

• Saturated A boolean value indicating whether the detector was saturated in one or more of the fluorescence channels. Saturating particles are highly fluorescent, but do not have a reliable group classification.

Comments

The expedition

Data were collected during the Arctic Ocean 2018 expedition with the Swedish icebreaker Oden, which was organised by the Swedish Polar Research Secretariat.

The Swedish Polar Research Secretariat (SPRS) provided access to the icebreaker Oden and logistical support in collaboration with the U.S. National Science Foundation. We are grateful to the Chief Scientists — Caroline Leck and Patricia Matrai — for planning, technical support, and coordination of Arctic Ocean 2018 expedition, to the SPRS logistical staff, and to icebreaker Oden’s Captain Mattias Peterson and his crew for expert field support.

Coordinates

Coordinates for the ship track of icebreaker Oden are provided in the datset Navigation, meteorological and surface seawater data from the Arctic Ocean 2018 expedition.

Associated article

Please refer to the publication by Kojoj et al. (2024) when referencing the dataset.