scholarly journals Effects of marine fuel sulfur restrictions on particle number concentrations and size distributions in ship plumes in the Baltic Sea

2021 ◽  
Vol 21 (4) ◽  
pp. 3215-3234
Author(s):  
Sami D. Seppälä ◽  
Joel Kuula ◽  
Antti-Pekka Hyvärinen ◽  
Sanna Saarikoski ◽  
Topi Rönkkö ◽  
...  

Abstract. Exhaust emissions from shipping are a major contributor to particle concentrations in coastal and marine areas. Previously, the marine fuel sulfur content (FSC) was restricted globally to 4.5 m/m%, but the limit was changed to 3.5 m/m% at the beginning of 2012 and further down to 0.5 m/m% in January 2020. In sulfur emission control areas (SECA), the limits are stricter: the FSC restriction was originally 1.50 m/m%, but it decreased to 1.00 m/m% in July 2010 and again to 0.10 m/m% in January 2015. In this work, the effects of the FSC restrictions on particle number concentrations (PNCs) and particle number size distributions (NSDs) are studied in the Baltic Sea SECA. Measurements were made on a small island (Utö, Finland; 59∘46′50 N, 21∘22′23 E) between 2007 and 2016. Ship plumes were extracted from the particle number size distribution data, and the effects of the FSC restrictions on the observed plumes as well as on the ambient concentrations were investigated. Altogether, 42 322 analyzable plumes were identified during the 10-year measurement period. The results showed that both changes in the FSC restrictions reduced the PNCs of the plumes. The latter restriction (to 0.10 m/m% in January 2015) also decreased the ambient particle number concentrations, as a significant portion of particles in the area originated from ship plumes that were diluted beyond the plume detection limits. The overall change in the PNCs of the plumes and ambient air was 27 and 32 %, respectively, for the total FSC change from 1.50 m/m% to 0.10 m/m%. The decrease in the plume particle number concentration was caused mostly by a decrease in the concentration of particle sizes of between approximately 33 and 144 nm. The latter restriction also reduced the geometric mean diameter of the particles, which was probably caused by the fuel type change from residual oil to distillates during the latter restriction. The PNC was larger for the plumes measured at daytime than for those measured at nighttime, likely because of the photochemical aging of particles due to UV light. The difference decreased with decreasing FSC, indicating that a lower FSC also has an impact on the atmospheric processing of ship plumes.

2020 ◽  
Author(s):  
Sami Seppälä ◽  
Joel Kuula ◽  
Antti-Pekka Hyvärinen ◽  
Sanna Saarikoski ◽  
Topi Rönkkö ◽  
...  

Abstract. Exhaust emissions from shipping are a major contributor to particle concentrations in coastal and marine areas. Previously, marine fuel sulfur content (FSC) was restricted globally to 4.5 m/m% but the limit was changed to 3.5 m/m% at the beginning of 2012 and further down to 0.5 m/m% in January 2020. In sulfur emission control areas (SECA), the limits are stricter; FSC restriction was originally 1.50 m/m% but it decreased first to 1.00 m/m% in July 2010 and again to 0.10 m/m% in January 2015. In this work, the effects of the FSC restrictions on particle number concentrations (PNC) and size distributions (NSD) are studied at the Baltic Sea SECA. Measurements were made on a small island (Utö, Finland; 59° 46’50N, 21° 22’23E) between 2007 and 2016. Ship plumes were extracted from the particle number size distribution data, and the effects of the FSC restrictions on the observed plumes as well as on the total ambient concentrations were investigated. Altogether 42 322 analyzable plumes were identified during the 10-year measurement period. The results showed that both changes in the FSC restrictions reduced the PNC of the plumes. The latter restriction (to 0.10 m/m% in January 2015) decreased also the total ambient particle number concentrations, as a significant portion of particles in the area originated from ship plumes that were diluted beyond the plume detection limits. The overall change in the PNC of the plumes and ambient air was 27 and 32 %, respectively, for the total FSC change from 1.50 to 0.10 m/m%. The decrease in plume particle number concentration was caused mostly by a decrease in the concentration of particle sizes of ∼35–134 nm. The latter restriction also reduced the count median diameter of the particles, which was probably caused by the fuel type change from residual oil to distillates during the latter restriction. The PNC was larger for the plumes measured in daytime compared to those measured in nighttime likely because of the photochemical aging of particles due to UV-light. The difference decreased with the reducing FSC indicating that lower FSC has also an impact on the atmospheric processing of ship plumes.


2014 ◽  
Vol 7 (1) ◽  
pp. 149-161 ◽  
Author(s):  
L. Pirjola ◽  
A. Pajunoja ◽  
J. Walden ◽  
J.-P. Jalkanen ◽  
T. Rönkkö ◽  
...  

Abstract. Four measurement campaigns were performed in two different environments – inside the harbour areas in the city centre of Helsinki, and along the narrow shipping channel near the city of Turku, Finland – using a mobile laboratory van during winter and summer conditions in 2010–2011. The characteristics of gaseous (CO, CO2, SO2, NO, NO2, NOx) and particulate (number and volume size distributions as well as PM2.5) emissions for 11 ships regularly operating on the Baltic Sea were studied to determine the emission parameters. The highest particle concentrations were 1.5 × 106 and 1.6 × 105 cm−3 in Helsinki and Turku, respectively, and the particle number size distributions had two modes. The dominating mode peaked at 20–30 nm, and the accumulation mode at 80–100 nm. The majority of the particle mass was volatile, since after heating the sample to 265 °C, the particle volume of the studied ship decreased by around 70%. The emission factors for NOx varied in the range of 25–100 g (kg fuel)−1, for SO2 in the range of 2.5–17.0 g (kg fuel)−1, for particle number in the range of (0.32–2.26) × 1016 # (kg fuel)−1, and for PM2.5 between 1.0–4.9 g (kg fuel)−1. The ships equipped with SCR (selective catalytic reduction) had the lowest NOx emissions, whereas the ships with DWI (direct water injection) and HAMs (humid air motors) had the lowest SO2 emissions but the highest particulate emissions. For all ships, the averaged fuel sulphur contents (FSCs) were less than 1% (by mass) but none of them was below 0.1% which will be the new EU directive starting 1 January 2015 in the SOx emission control areas; this indicates that ships operating on the Baltic Sea will face large challenges.


2013 ◽  
Vol 6 (4) ◽  
pp. 7149-7184
Author(s):  
L. Pirjola ◽  
A. Pajunoja ◽  
J. Walden ◽  
J.-P. Jalkanen ◽  
T. Rönkkö ◽  
...  

Abstract. Four measurement campaigns by a mobile laboratory van were performed in two different environments; inside the harbour areas in the city center of Helsinki and along the narrow shipping channel near the city of Turku, Finland, during the winter and summer conditions in 2010–2011. The characteristics of gaseous (CO, CO2, SO2, NO, NO2, NOx) and particulate (number and volume size distributions as well as PM2.5) emissions for 11 ships regularly operating on the Baltic Sea were studied to determine the emission parameters. The highest particle concentrations were 1.5 × 106 and 1.6 × 105 cm−3 in Helsinki and Turku, respectively, and the particle number size distributions had two modes. The dominating mode was peaking at 20–30 nm and the accumulation mode at 80–100 nm. The majority of the particle mass was volatile since after heating the sample to 265 °C, the particle volume of the studied ships decreased by around 70%. The emission factors for NOx varied in the range of 25–100 g (kg fuel)−1, for SO2 in the range of 2.5–17.0 g (kg fuel)−1, for particle number in the range of (0.32–2.26) × 1016 particles (kg fuel)−1, and for PM2.5 between 1.0–4.9 g (kg fuel)−1. The ships equipped with SCR had lowest NOx emissions whereas the ships with DWI and HAM had lowest SO2 emissions but highest particulate emissions. For all ships the averaged fuel sulphur contents (FSCs) were less than 1% (by mass) but none of those was below 0.1% which will be the new EU directive from 1 January 2015 in the SOx Emission Control Areas, indicating big challenges for ships operating on the Baltic Sea.


2018 ◽  
Vol 58 ◽  
pp. 01002
Author(s):  
Michalina Bielawska ◽  
Oskar Czechowski ◽  
Ernest Czermański ◽  
Aneta Oniszczuk-Jastrząbek ◽  
Tomasz Owczarek

The purpose of this research is to attempt to evaluate the extent, to which technical standards related to marine fuels and thereby also sulphur dioxide (SO2) content in engine exhausts from vessels operating on the Baltic Sea have been effective in curbing the negative impact of marine shipping on air quality, in particular in port cities. Marine environment protection is governed by the provisions of the MARPOL 73/78 International Convention, which Poland ratified as a party. Different areas of concern for marine shipping have been regulated in separate Appendices to the Convention. The first step was to introduce severe restrictions on SOx emissions in view of the fact that heavy marine fuel is the lowest-quality kerosene-derived fuel with a large content of sulphur. A gradual process was put in place to reduce its content in marine fuel. As a consequence, the world’s marine areas were divided into sulphur emission control areas (also known as SECA) and other areas. In Europe, these areas include the entire Baltic Sea and large portions of the North Sea. Another important technical and economic measure was to lower the limit of sulphur content in marine fuel to 0.1% in all SECA areas, with the limits remaining unchanged in the other areas. Two dates were of key importance for the investigation: 2010, when the reduction in sulphur content of marine fuels from 1.5% to 1% was mandated, and 2015, when the standard for sulphur content was dramatically lowered to 0.1%. In the first stage, the concentration of sulphur dioxide was researched as one of the factors preceding air contamination with suspended particles in the Gdańsk - Gdynia area in the period from 2005 to 2016, as investigated by four automatic reference measurement stations in the ARMAAG network (hourly data) located in the immediate vicinity of the sea (AM4, AM5, AM6 and AM8). The research concerned the arrival of high concentrations of sulphur blown in from the sea by the wind. Another key factor was the secondary data on the number of ships, in the form of monthly series, starting from 2007. The analysis was performed in stages. In the first stage, the quality of measurement and secondary data were evaluated using a unique data quality assessment method. Further on, Principal Component Analysis (PCA) models were constructed to identify spatial correlations between SO2 concentration distributions, which were used later as a basis on which to determine synthetic measures of average hourly concentrations for the entire agglomeration area. Subsequently, the impact of the SO2 source (influx from the Baltic Sea to the agglomeration areas) was gauged separately for each individual station. The PCA models constructed on the basis of hourly data corroborated the synthetic measures as correct, making it possible to identify the similarity of concentration distributions across the investigated stations. Multi-Dimensional Regression Models and Generalized Regression Models (GRM) have made it possible to identify the period, in which the concentration of sulphur dioxide dropped steadily (from 2010 to 2016), as well as the seasonal impact of variation in SO2 concentration and the number of ships. The hourly data was converted to average monthly, quarterly and annual values, depending on the mathematical model and purpose of research.


2017 ◽  
Author(s):  
Joachim Kuss ◽  
Siegfried Krüger ◽  
Johann Ruickoldt ◽  
Klaus-Peter Wlost

Abstract. Marginal seas are directly subjected to anthropogenic and natural influences from land in addition to receiving inputs from the atmosphere and open ocean. Together these lead to pronounced gradients and strong dynamic changes. However, in the case of mercury emissions from these seas, estimates often fail to adequately account for the spatial and temporal variability of the elemental mercury concentration in surface water (Hg0wat). In this study, a method to measure Hg0wat at high resolution was devised and subsequently validated. The better-resolved Hg0wat dataset, consisting of about one measurement per nautical mile, yielded insight into the sea's small-scale variability and thus improved the quantification of the sea's Hg0 emissions, a major source of atmospheric mercury. Research campaigns in the Baltic Sea were carried out between 2011 and 2015 during which Hg0 both in surface water and in ambient air were measured. For the former, two types of equilibrators were used. A membrane equilibrator enabled continuous equilibration and a bottle equilibrator assured that equilibrium was reached for validation. The measurements were combined with data obtained in the Baltic Sea in 2006 from a bottle equilibrator only. The Hg0 sea-air flux was newly calculated with the combined dataset based on current knowledge of the Hg0 Schmidt number, Henry's law constant, and a widely used gas-exchange transfer velocity parameterization. By using a newly developed pump-CTD with increased pumping capability in the Hg0 equilibrator measurements, Hg0wat could also be characterized in deeper water layers. A process study carried out near the Swedish island Øland in August 2015 showed that the upwelling of Hg0-depleted water contributed to Hg0 emissions of the Baltic Sea. However, a delay of a few days after contact between the upwelled water and light was apparently necessary before the biotic and abiotic transformations of ionic to volatile Hg0 produced a distinct sea-air Hg0 concentration gradient. This study clearly showed spatial, seasonal, and interannual variability in the Hg0 sea-air flux of the Baltic Sea. The average annual Hg0 emission was 0.90 ± 0.18 Mg for the Baltic Proper and to 1.73 ± 0.32 Mg for the entire Baltic Sea, which is about half the amount entrained by atmospheric deposition. A comparison of our results with the Hg0 sea-air fluxes determined in the Mediterranean Sea and in marginal seas in East Asia were to some extent similar but they partly differed in terms of the deviations in the amount and seasonality of the flux.


2003 ◽  
Vol 3 (6) ◽  
pp. 2083-2099 ◽  
Author(s):  
O. Hertel ◽  
C. Ambelas Skjøth ◽  
J. Brandt ◽  
J. H. Christensen ◽  
L. M. Frohn ◽  
...  

Abstract. A new model system for mapping and forecasting nitrogen deposition to the Baltic Sea has been developed. The system is based on the Lagrangian variable scale transport-chemistry model ACDEP (Atmospheric Chemistry and Deposition model), and aims at delivering deposition estimates to be used as input to marine ecosystem models. The system is tested by comparison of model results to measurements from monitoring stations around the Baltic Sea. The comparison shows that observed annual mean ambient air concentrations and wet depositions are well reproduced by the model. Diurnal mean concentrations of NHx (sum of NH3 and NH4+) and NO2 are fairly well reproduced, whereas concentrations of total nitrate (sum of HNO3 and NO3-) are somewhat overestimated. Wet depositions of nitrate and ammonia are fairly well described for annual mean values, whereas the discrepancy is high for the monthly mean values and the wet depositions are rather poorly described concerning the diurnal mean values. The model calculations show that the annual atmospheric nitrogen deposition has a pronounced south--north gradient with depositions in the range about 1.0 T N km-2 in the south and 0.2 T N km-2 in the north. The results show that in 1999 the maximum diurnal mean deposition to the Danish waters appeared during the summer in the algae growth season. For the northern parts of the Baltic the highest depositions were distributed over most of the year. Total deposition to the Baltic Sea was for the year 1999 estimated to 318 kT N for an area of 464 406 km2 equivalent to an average deposition of 684 kg N/km2.


2021 ◽  
Vol 21 (24) ◽  
pp. 18175-18194
Author(s):  
Jari Walden ◽  
Liisa Pirjola ◽  
Tuomas Laurila ◽  
Juha Hatakka ◽  
Heidi Pettersson ◽  
...  

Abstract. Fluxes of gaseous compounds and nanoparticles were studied using micrometeorological methods at Harmaja in the Baltic Sea. The measurement site was situated beside the ship route to and from the city of Helsinki. The gradient (GR) method was used to measure fluxes of SO2, NO, NO2, O3, CO2, and Ntot (the number concentration of nanoparticles). In addition, the flux of CO2 was also measured using the eddy-covariance (EC) method. Distortion of the flow field caused by obstacles around the measurement mast was studied by applying a computation fluid dynamic (CFD) model. This was used to establish the corresponding heights in the undisturbed stream. The wind speed and the turbulent parameters at each of the established heights were then recalculated for the gradient model. The effect of waves on the boundary layer was taken into consideration, as the Monin–Obukhov theory used to calculate the fluxes is not valid in the presence of swell. Uncertainty budgets for the measurement systems were constructed to judge the reliability of the results. No clear fluxes across the air–sea nor the sea–air interface were observed for SO2, NO, NO2, NOx (= NO + NO2), O3, or CO2 using the GR method. A negative flux was observed for Ntot, with a median value of −0.23 × 109 m−2 s−1 and an uncertainty range of 31 %–41 %. For CO2, while both positive and negative fluxes were observed, the median value was −0.081 μmol m−2 s−1 with an uncertainty range of 30 %–60 % for the EC methods. Ship emissions were responsible for the deposition of Ntot, while they had a minor effect on CO2 deposition. The fuel sulfur content (FSC) of the marine fuel used in ships passing the site was determined from the observed ratio of the SO2 and CO2 concentrations. A typical value of 0.40 ± 0.06 % was obtained for the FSC, which is in compliance with the contemporary FSC limit value of 1 % in the Baltic Sea area at the time of measurements. The method to estimate the uncertainty in the FSC was found to be accurate enough for use with the latest regulations, 0.1 % (Baltic Sea area) and 0.5 % (global oceans).


Author(s):  
Hanna Hoeglind ◽  
Sofia Eriksson ◽  
Katarina Gardfeldt

Mercury is a toxic pollutant emitted from both natural sources and through human activities. A global interest in atmospheric mercury has risen ever since the discovery of the Minamata disease in 1956. Properties of gaseous elemental mercury enable long range transport which can cause pollution even in pristine environments. Total gaseous mercury (TGM) was measured from winter 2016 to spring 2017 over the Baltic Sea. A Tekran 2357A mercury analyser was installed aboard the research and icebreaking vessel Oden for the purpose of continuous measurements of gaseous mercury in ambient air. Measurements were performed during a campaign along the Swedish east coast and in the Bothnian Bay near Lulea during the icebreaking season. Data was evaluated from Gothenburg using a plotting software and back trajectories for air masses were calculated. The TGM average of 1.365 ± 0.054 ng/m3 during winter and 1.288 ± 0.140 ng/m3 during spring was calculated as well as a total average of 1.362 ± 0.158 ng/m3. Back trajectories showed a possible correlation of anthropogenic sources elevating the mercury background level in some areas. There were also indications of depleted air, i.e., air with lower concentrations than average, being transported from the Arctic to northern Sweden resulting in a drop in TGM levels.


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