Absorption coefficient for urban background air, Stockholm, December 2018

Roxana Cremer, Paul Zieger, Johan Ström

The dataset includes three parallel absorption coefficient measurements by two different types of instruments: one Multi-Angle Absorption Photometer (MAAP) and two Particle Soot/Absorption Photometers (PSAP) to evaluate the performance and comparability.

The instruments were set up next to each other in the lab at Stockholm University and measured the same sample flow of ambient air through the same inlet for 7 days in wintertime. The location is considered urban background. The data can be used to get a measure of black carbon concentration in the air.

The data were collected at Stockholm University, Stockholm, Sweden from 2018-12-14 12:00 until 2018-12-21 13:40. All data were corrected according to established procedures and the minute values were averaged to 10-minute time stamps. An influence from a nearby highway with rush hours can be seen in addition to a diurnal trend.

Citation

Roxana Cremer, Paul Zieger, Johan Ström (2020) Absorption coefficient for urban background air, Stockholm, December 2018. Dataset version 1. Bolin Centre Database. https://doi.org/10.17043/cremer-2020-urban-background-1

References

Tunved P, Cremer RS, Zieger P, Ström J (2021) Using correlations between observed equivalent black carbon and aerosol size distribution to derive size resolved BC mass concentration: a method applied on long-term observations performed at Zeppelin station, Ny-Ålesund, Svalbard, Tellus B: Chemical and Physical Meteorology 73:1, 1-17. https://doi.org/10.1080/16000889.2021.1933775

Bond TC, Anderson TL, Campbell D (1999) Calibration and intercomparison of filter-based measurements of visible light absorption by aerosols. Aerosol Science and Technology, 30, 582⁠ – ⁠600. https://doi.org/10.1080/027868299304435

Data description

There is one datafile, in semicolon-separated (.csv) format, with data columns structured in the following way:

• Date and Time in the format yyyy-mm-dd HH:MM:SS
• Absorption coefficient of the instruments: PSAP1; MAAP526; MAAP637; PSAP2

All data are in the unit m⁻¹ and are 10-minute averages. The PSAP instruments are costume made by ACES luftlab, at the Department of Environmental Science, and measure at the wavelength of 526 nm. The dataset was measured on a minute based time interval and corrected according to Bond et al. (1999). The MAAP instrument measures on 637 nm, additionally it was corrected to 526 nm.

Instrumentation: From Centre for Atmospheric Science, University of Manchester — MAAP and PSAP and DMPS.

The method and structure of the experiment is explained in more detail by Tunved et al. (2020).

Comments

The data show a peak in the middle of the night (2018-12-17). The cause for this could not be determined in detail but one assumption is the snow cleaning machine that cleaned the roads around the buildings and the aerosol inlet during this time of the year.