![]() ![]() Instead, statistically significant recovery in TRW is linked to the trajectory of annual SO 2 concentrations or sulfur deposition at all three stands.Ĭentral Europe was heavily polluted by SO 2 originating from the burning of high sulfur lignite for electricity generation. Across the long-term site history, changes in soil chemistry (pH, base saturation, Bc/Al soil solution ratio) cannot explain observed changes in TRW at the two study sites where we tracked soil chemistry. ![]() TRW recovery was interrupted in 1996 when highly acidic rime (originating from more pronounced decline of alkaline dust than SO 2 from local power plants) injured the spruce canopy, but recovered soon to the pre-episode growth. Despite large increases in soil base saturation, as well as soil pH, as a result of repeated liming starting in 1981, TRW growth was similar in limed and unlimed plots. Furthermore, recovery of TRW was similar in unlimed and limed stands. In this study we oserved that annual tree ring width (TRW) declined in the 1970s and subsequently recovered in the 1990s, tracking SO 2 concentrations closely. ![]() In contrast, acidic atmospheric deposition declined by 80% and atmospheric SO 2 concentration by 90% between the late 1980s and 2010s. Extensive soil acidification occurred in the highly polluted "Black Triangle" in Central Europe, and upper mineral soils are still acidified. SO 2 concentrations, high acidic deposition to the forest canopy) plays a dominant role in driving forest health. Retrospective analysis of Norway spruce ( Picea abies) tree rings in the Czech Republic shows that air pollution (e.g. The IMO agreed in 2011 on an investigation plan to gather information and to find possible black carbon control measures for future regulations, which to some extent can be delivered through this article.The forests of central Europe have undergone remarkable transitions in the past 40 years as air quality has improved dramatically. The IMO is the law-maker/the United Nations specialized agency with responsibility for atmospheric pollution by ships in international waters. This manuscript is especially interesting for the International Maritime Organization (IMO) and its sub-committee on Pollution Prevention and Response (PPR). Implications: The manuscript describes a small efficient system for the removal of particle matter and black carbon particles from the exhaust gas generated by a ship engine. ![]() The study indicates that a similar removal efficiency between black carbon and particulate matter could be achieved and that the main focus for improvement of black carbon removal should be found in the particle range between 0.02 and 0.77 μm. By investigating the removal efficiencies of different particle sizes and black carbon content, it was found that the best fit was achieved for sizes between 0.02 and 0.77 μm, indicating a black carbon size range in this order. A change in particle residence time (0.3 to 0.95 s) showed an overall removal increase of 31.7% and revealed removal efficiency gaps of up to 24.1% between particle sizes. The wet electrostatic precipitator was able to remove from 42.7% to 97.2% of the particulate matter and 44.8% to 95.9% of black carbon particles by varying the electrical energy input to the gas stream (5-262 J/m3) and the particle residence time (0.3-1.8 s). Three key parameters, voltage-current characteristics, transferred electrostatic energy to the exhaust gas, and particle residence times were varied to evaluate their effects on removal efficiencies. The exhaust gas cleaned during the experiments was produced by a 2 MW marine engine operated on heavy fuel oil. This article reports the removal efficiency of black carbon, total particulate matter, and various particle sizes using different operating conditions in a full-scale hexagonal wet electrostatic precipitator column with sequential cleaning. Among the operational parameters of wet electrostatic precipitators, particle residence times (<1 s) and the amount of electrostatic energy transferred to the exhaust gas are important to determine the removal efficiencies of wet electrostatic precipitators. The absence of studies investigating the removal of black carbon particles using a wet electrostatic precipitator requires additional development/investigations. Wet electrostatic precipitators have demonstrated a robust capability for removal of particulate matter by minimizing back corona and particle re-entrainment of fine particles. ![]()
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