Impact of a nitrogen emission control area (NECA) on the future air quality and nitrogen deposition to seawater in the Baltic Sea region

Abstract

<p><strong>Abstract.</strong> Air pollution due to shipping is a serious concern for coastal regions in Europe. Shipping emissions of nitrogen oxides (NO<sub>x</sub>) to air on the Baltic Sea are of similar magnitude (330 kt y<sup>−1</sup>) as the combined land-based NO<sub>x</sub> emissions from Finland and Sweden in all emission sectors. Deposition of nitrogen compounds originating from shipping activities contribute to eutrophication of the Baltic Sea and coastal areas in the Baltic Sea region. For the North Sea and the Baltic Sea a nitrogen emission control area (NECA) will become effective in 2021; in accordance with the International Maritime Organization (IMO) target of reducing NO<sub>x</sub> emissions from ships. Future scenarios for 2040 were designed to study the effect of enforced and planned regulation of ship emissions and the fuel efficiency development on air quality and nitrogen deposition. The Community Multiscale Air Quality (CMAQ) model was used to simulate the current and future air quality situation. The meteorological fields, the emissions from ship traffic and the emissions from land-based sources were considered at a grid resolution of 4 × 4 km<sup>2</sup> for the Baltic Sea region in nested CMAQ simulations. Model simulations for the present-day (2012) air quality show that shipping emissions are the major contributor to atmospheric nitrogen dioxide (NO<sub>2</sub>) concentrations over the Baltic Sea. In the business as usual (BAU) scenario, with the introduction of the NECA, NO<sub>x</sub> emissions from ship traffic in the Baltic Sea are reduced by about 80 % in 2040. An approximate linear relationship was found between ship emissions of NO<sub>x</sub> and the simulated levels of annual average NO<sub>2</sub> over the Baltic Sea in year 2040, when following different future shipping scenarios. The burden of fine particulate matter (PM<sub>2.5</sub>) over the Baltic Sea region is predicted to decrease by 35–37 % between 2012 and 2040. The reduction of PM<sub>2.5</sub> is larger over sea, where it drops by 50–60 % along the main shipping routes, and smaller over the coastal areas. The introduction of NECA is critical for reducing ship emissions of NO<sub>x</sub> to levels that are low enough to sustainably dampen ozone (O<sub>3</sub>) production in the Baltic Sea region. A second important effect of the NECA over the Baltic Sea region is the reduction of secondary formation of particulate nitrate. This lowers the ship-related PM<sub>2.5</sub> by 72 % in 2040 compared to present-day, while it is reduced by only 48 % without implementation of the NECA. The effect of a lower fuel efficiency development on the absolute ship contribution of air pollutants is limited. Still, the annual mean ship contributions in 2040 to NO<sub>2</sub>, sulphur dioxide and PM<sub>2.5</sub> and daily maximum O<sub>3</sub> is significantly higher if a slower fuel efficiency development is assumed. Nitrogen deposition to the seawater of the Baltic Sea decreases on average by 40–44 % between 2012 and 2040 in the simulations. The effect of the NECA on nitrogen deposition is most significant in the western part of the Baltic Sea. It will be important to closely monitor compliance of individual ships with the planned nitrogen emission regulations.</p>

On the Ship Particle Number Emission Index: Size‐Resolved Microphysics and Key Controlling Parameters

“…cm −3 s −1 and the N SP and EIPN SP to decrease by approximately 1 order of magnitude. There is a NO x emission control region around Europe (Karl et al., 2019) and our study indicate that such a control may slightly decrease the formation of new particles in ship plumes. Figures 8b and 8c give EIPN TP , EIPN SP , EIPN PP , two‐hour averaged concentration of H 2 SO 4 , two‐hour averaged nucleation rate (J), and N SP as a function of ambient [NO x ] and [O 3 ], respectively.…”

Climate Change in the Baltic Sea Region: A Summary

“…This effect is pronounced in the south-western Baltic Sea area (Quante et al, 2021). Exact numbers from such modelling should still be interpreted with care, as shown by Karl et al (2019a), who compared output from three state-of-the-art chemistry transport models for the Baltic Sea area.…”

“…For the Baltic Sea, a nitrogen emission control area (NECA) will become effective in 2021. Karl et al (2019a) designed future scenarios to study the effect of current and planned regulations of ship emissions and the expected fuel efficiency development on air quality in the Baltic Sea region. They showed that in a business-as-usual scenario for 2040 (SECA-0.1% and fuel efficiency regulation effective starting in 2015), the introduction of the NECA will reduce NOX emissions from ship traffic in the Baltic Sea by about 80% in 2040.…”

The impact of ship emissions on air quality and human health in the Gothenburg area – Part I: 2012 emissions

“…The chemical boundary conditions were taken from the Community Multi-scale Air Quality Modelling System (CMAQ) (Byun and Ching, 1999;Byun and Schere, 2006). CMAQ model simulations on a 4 km × 4 km grid (Karl et al, 2019c), which were used for the chemical boundary conditions, were driven by the high-resolution meteorology meteorological fields of the 245 COSMO-CLM (Rockel et al, 2008) version 5.0 using the ERA-Interim re-analysis as forcing data. Chemical boundary conditions for the CMAQ model simulations were provided through hemispheric CTM simulations, from a SILAM model (Sofiev et al, 2006) run on a 0.5˚ × 0.5˚ grid resolution, which was provided by Finnish Meteorological Institute (FMI).…”