Effects of marine fuel sulfur restrictions on particle properties in atmospheric aerosol at the Baltic Sea
Seppälä, Sami (2020)
Seppälä, Sami
2020
Teknis-luonnontieteellinen DI-tutkinto-ohjelma - Degree Programme in Science and Engineering, MSc (Tech)
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.
Hyväksymispäivämäärä
2020-03-04
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202002061886
https://urn.fi/URN:NBN:fi:tuni-202002061886
Tiivistelmä
Emissions produced by shipping have been shown to have a significant effect on the climate and the human health especially in coastal areas. It is estimated that typically the emissions produced by shipping have in total a cooling effect on the climate as negative radiative forcing (RF) induced by refractive particulate matter (PM) negates the warming effect of greenhouse gases (GHGs) emitted in shipping. However, this effect is not uniform and, in some areas, for example in the Arctic the net effect of shipping on the climate might also be warming. The shipping emissions also contribute to the acidification of marine environments. The effects of shipping emissions on the human health are negative. The shipping emissions have been shown to lead to increased premature mortality and numerous respiratory diseases.
This work focuses on the effects of the different marine fuel sulfur restrictions of 1.50 %, 1.00 % and 0.10 % on the atmospheric aerosol and ship plumes in the Baltic Sea Sulfur Emission Control Area (SECA). The discussed properties are total particle number concentration (PNC), particle number concentration over background particle number concentration during plume (PNCpl), the direct contribution of the PNCpl to the total PNC, the number size distribution of the plume particles (NSDpl), the number size distribution of the background particles (NSDbg), the surface area concentration of the plume particles (PSCpl) and plume aging. The NSDpls are also compared to NSDs from direct emission measurements. The measurement data used in this work is differential mobility particle sizer (DMPS) data measured by the Finnish Meteorological Institute at the measurement station of Utö in the Baltic Sea between 11.1.2007-31.12.2016. The DMPS data was used with the Automatic Identification System (AIS) and weather data to produce the results. In this work the plumes were analyzed from three different sectors with the plumes arriving from different distances on average. The goal of this work was to study if the ship plumes are detectable in the atmospheric measurement data and how the sulfur restrictions influence the particle properties of the atmospheric aerosol. This work may give better understanding what kind of an effect the sulfur restrictions have on the atmospheric aerosol and how the measurement system at Utö could be developed in the future.
In total 43503 analyzable plumes were detected from the DMPS data. The sulfur restrictions were found to be effective, reducing both the PNCs and average particle diameters. The effect of the change in the sulfur restriction from 1.50 % to 1.00 % was much smaller than the effect of the later change in the sulfur restriction from 1.00 % to 0.10 %. These effects of the sulfur restriction changes were observed both in the plumes and the background aerosol particles. The most significant effects of the changes in the sulfur restrictions were: 1) The increase of the PNCpls in particles sizes smaller than 35 nm, while the PNCpls in total decreased. This increase was related to the reduced size of the particles produced in the combustion process. 2) The sulfur restrictions were found to decrease the largest average PNCpls. Especially the PNCpls of the plumes with the largest diameters of the maximums of the NSDpls were reduced. 3) The lower sulfur contents in marine fuels led to larger relative increases of the PNCpls in the smaller particles in the plume aging compared to the higher sulfur contents. 4) The stricter sulfur reductions shifted the maximums of the NSDbgs to smaller particle sizes and reduced the PNCbgs indicating that the effect of the shipping emissions on the atmospheric aerosol is a lot larger than what only the direct effects would suggest. 5) The measurement cycle of the DMPS (5 min 20 s) was found to be too long for the optimal plume detection and using an instrument with a shorter time resolution would be beneficial.
This work focuses on the effects of the different marine fuel sulfur restrictions of 1.50 %, 1.00 % and 0.10 % on the atmospheric aerosol and ship plumes in the Baltic Sea Sulfur Emission Control Area (SECA). The discussed properties are total particle number concentration (PNC), particle number concentration over background particle number concentration during plume (PNCpl), the direct contribution of the PNCpl to the total PNC, the number size distribution of the plume particles (NSDpl), the number size distribution of the background particles (NSDbg), the surface area concentration of the plume particles (PSCpl) and plume aging. The NSDpls are also compared to NSDs from direct emission measurements. The measurement data used in this work is differential mobility particle sizer (DMPS) data measured by the Finnish Meteorological Institute at the measurement station of Utö in the Baltic Sea between 11.1.2007-31.12.2016. The DMPS data was used with the Automatic Identification System (AIS) and weather data to produce the results. In this work the plumes were analyzed from three different sectors with the plumes arriving from different distances on average. The goal of this work was to study if the ship plumes are detectable in the atmospheric measurement data and how the sulfur restrictions influence the particle properties of the atmospheric aerosol. This work may give better understanding what kind of an effect the sulfur restrictions have on the atmospheric aerosol and how the measurement system at Utö could be developed in the future.
In total 43503 analyzable plumes were detected from the DMPS data. The sulfur restrictions were found to be effective, reducing both the PNCs and average particle diameters. The effect of the change in the sulfur restriction from 1.50 % to 1.00 % was much smaller than the effect of the later change in the sulfur restriction from 1.00 % to 0.10 %. These effects of the sulfur restriction changes were observed both in the plumes and the background aerosol particles. The most significant effects of the changes in the sulfur restrictions were: 1) The increase of the PNCpls in particles sizes smaller than 35 nm, while the PNCpls in total decreased. This increase was related to the reduced size of the particles produced in the combustion process. 2) The sulfur restrictions were found to decrease the largest average PNCpls. Especially the PNCpls of the plumes with the largest diameters of the maximums of the NSDpls were reduced. 3) The lower sulfur contents in marine fuels led to larger relative increases of the PNCpls in the smaller particles in the plume aging compared to the higher sulfur contents. 4) The stricter sulfur reductions shifted the maximums of the NSDbgs to smaller particle sizes and reduced the PNCbgs indicating that the effect of the shipping emissions on the atmospheric aerosol is a lot larger than what only the direct effects would suggest. 5) The measurement cycle of the DMPS (5 min 20 s) was found to be too long for the optimal plume detection and using an instrument with a shorter time resolution would be beneficial.