An operational urban air quality model ENFUSER, based on dispersion modelling and data assimilation.

An operational urban air quality modelling system ENFUSER is presented with an evaluation against measured data. ENFUSER combines several dispersion modelling approaches, uses data assimilation, and continuously extracts information from online, global open-access sources. The modelling area is described with a combination of geographic datasets. These GIS datasets are globally available with open access, and therefore the model can be applied worldwide. Urban scale dispersion is addressed with a combination of Gaussian puff and Gaussian plume modelling, and long-range transport of pollutants is accounted for via a separate regional model. The presented data assimilation method, which supports the use of AQ sensors and incorporates a longer-term learning mechanism, adjusts emission factors and the regional background values on an hourly basis. The model can be used with reasonable accuracy also in urban areas, for which detailed emissions inventories would not be available, due to the data assimilation capabilities.

Underwater noise emissions from ships during 2014-2020.

This paper reports trends in the input of underwater noise source energy emission from global shipping, based on bottom-up modeling of individual ships. In terms of energy, we predict the doubling of global shipping noise emissions every 11.5 years, on average, but there are large regional differences. Shipping noise emissions increase rapidly in Arctic areas and the Norwegian Sea. The largest contributors are the containerships, dry bulk and liquid tanker vessels which emit 75% of the underwater shipping noise source energy. The COVID-19 pandemic changed vessel traffic patterns and our modeling indicates a reduction of -6% in global shipping noise source energy in the 63 Hz ⅓ octave band. This reduction was largest in the Greenland Sea, the Coastal Waters of Southeast Alaska and British Columbia as well as the Gulf of California, temporarily disrupting the increasing pre-pandemic noise emission trend. However, in some sea areas, such as the Indian Ocean, Yellow Sea and Eastern China Sea the emitted noise source energy was only slightly reduced. In global scale, COVID-19 pandemic reduced the underwater shipping noise emissions close to 2017 levels, but it is expected that the increasing trend of underwater noise emissions will continue when the global economy recovers.

Modelling spatial dispersion of contaminants from shipping lanes in the Baltic Sea.

Major sources of pollution from shipping to marine environments are antifouling paint residues and discharges of bilge, black, grey and ballast water and scrubber discharge water. The dispersion of copper, zinc, naphthalene, pyrene, and dibromochloromethane have been studied using the Ship Traffic Emission Assessment Model, the General Estuarine Transport Model, and the Eulerian tracer transport model in the Baltic Sea in 2012. Annual loads of the contaminants ranged from 10-2 tons for pyrene to 100 s of tons for copper. The dispersion of the contaminants is determined by the surface kinetic energy and vertical stratification at the location of the discharge. The elevated concentration of the contaminants at the surface persists for about two-days and the contaminants are dispersed over the spatial scale of 10-60 km. The Danish Sounds, the southwestern Baltic Sea and the Gulf of Finland are under the heaviest pressure of shipborne contaminants in the Baltic Sea.

Shipping Remains a Globally Significant Source of Anthropogenic PN Emissions Even after 2020 Sulfur Regulation.

Shipping is the main source of anthropogenic particle emissions in large areas of the globe, influencing climate, air quality, and human health in open seas and coast lines. Here, we determined, by laboratory and on-board measurements of ship engine exhaust, fuel-specific particle number (PN) emissions for different fuels and desulfurization applied in shipping. The emission factors were compared to ship exhaust plume observations and, furthermore, exploited in the assessment of global PN emissions from shipping, utilizing the STEAM ship emission model. The results indicate that most particles in the fresh ship engine exhaust are in ultrafine particle size range. Shipping PN emissions are localized, especially close to coastal lines, but significant emissions also exist on open seas and oceans. The global annual PN produced by marine shipping was 1.2 × 1028 (±0.34 × 1028) particles in 2016, thus being of the same magnitude with total anthropogenic PN emissions in continental areas. The reduction potential of PN from shipping strongly depends on the adopted technology mix, and except wide adoption of natural gas or scrubbers, no significant decrease in global PN is expected if heavy fuel oil is mainly replaced by low sulfur residual fuels. The results imply that shipping remains as a significant source of anthropogenic PN emissions that should be considered in future climate and health impact models.

Environmental impacts of grey water discharge from ships in the Baltic Sea.

Discharge of grey water from ships is today unregulated in most sea areas, including the Baltic Sea. Annually, an estimated 5.5 million m3 grey water is emitted to the Baltic Sea with largest contribution from RoPax (4.25 million m3) and cruise ships (0.65 million m3). In total 44 different contaminants in grey water was identified and sorted into the sub categories organic compounds (28) and metals (16). Zinc and copper had the highest average concentrations with yearly inputs of 2.8 tons (zinc) and 1.5 tons (copper). 159 tons of nitrogen and 26.4 tons of phosphorus were estimated to be discharged to the Baltic Sea annually. An environmental risk assessment of contaminants, performed at a shipping lane in the Baltic Sea, showed the risk for adverse effects from grey water to be low. Nitrogen and phosphorus input from grey water contributes to 0.25% of the exceedance of, for the Baltic Sea set, eutrophication target.

Effect of ship emissions on O3 in the Yangtze River Delta region of China: Analysis of WRF-Chem modeling.

The Yangtze River Delta (YRD) region locates on the eastern coast of China, and it has suffered severe O3 pollutions due to high and mixed emissions of air pollutants. There are 3 different emission sectors for O3 precursors in the region, including anthropogenic VOCS and NOX emissions, ship emissions (mainly NOX), and biogenic emissions from a large forest (biogenic VOCS). This unique emission mixture produces complicated chemical processes in studying the O3 pollutions in the region. This study aims to identify the contribution of the ship emissions to O3 pollutions, as well as the effect of mixing emissions on O3 pollutions in YRD. To identify the individual emission effect, the WRF-Chem model is used in this study. The model generally performs well in simulating meteorological parameters and air pollutants against observations in YRD. Sensitive study suggests that the ship emissions have important effects on the O3 concentrations over ocean and inland, with a maximum increase of 30-50 µg m-3 occurred mainly in the ship track regions. However, the ship emissions have a very complicated effect on the in-land O3 concentrations. In the north of Shanghai, the NOX concentrations are high due to high anthropogenic emissions, and a further increase in NOX emissions from ship results in depressing O3 chemical production. In contrast, in the south of Shanghai, there are high biogenic VOC emissions (mainly isoprene) and low NOx concentrations. As a result, the O3 concentrations are enhanced by 30-50 µg m-3, due to the mixing between ship and forest emissions. This study suggests that ship emissions play important roles in controlling O3 pollutions in YRD. Furthermore, the mixing emissions between ship, anthropogenic, and biogenic emissions in YRD produce a complicated O3 chemical production and need to be carefully considered in controlling strategy of O3 pollution in the region.

Shipborne nutrient dynamics and impact on the eutrophication in the Baltic Sea.

The Baltic Sea is a severely eutrophicated sea-area where intense shipping as an additional nutrient source is a potential contributor to changes in the ecosystem. The impact of the two most important shipborne nutrients, nitrogen and phosphorus, on the overall nutrient-phytoplankton-oxygen dynamics in the Baltic Sea was determined by using the coupled physical and biogeochemical model system General Estuarine Transport Model-Ecological Regional Ocean Model (GETM-ERGOM) in a cascade with the Ship Traffic Emission Assessment Model (STEAM) and the Community Multiscale Air Quality (CMAQ) model. We compared two nutrient scenarios in the Baltic Sea: with (SHIP) and without nutrient input from ships (NOSHIP). The model uses the combined nutrient input from shipping-related waste streams and atmospheric depositions originating from the ship emission and calculates the effect of excess nutrients on the overall biogeochemical cycle, primary production, detritus formation and nutrient flows. The shipping contribution is about 0.3% of the total phosphorus and 1.25-3.3% of the total nitrogen input to the Baltic Sea, but their impact to the different biogeochemical variables is up to 10%. Excess nitrogen entering the N-limited system of the Baltic Sea slightly alters certain pathways: cyanobacteria growth is compromised due to extra nitrogen available for other functional groups while the biomass of diatoms and especially flagellates increases due to the excess of the limiting nutrient. In terms of the Baltic Sea ecosystem functioning, continuous input of ship-borne nitrogen is compensated by steady decrease of nitrogen fixation and increase of denitrification, which results in stationary level of total nitrogen content in the water. Ship-borne phosphorus input results in a decrease of phosphate content in the water and increase of phosphorus binding to sediments. Oxygen content in the water decreases, but reaches stationary state eventually.

Cleaner fuels for ships provide public health benefits with climate tradeoffs.

We evaluate public health and climate impacts of low-sulphur fuels in global shipping. Using high-resolution emissions inventories, integrated atmospheric models, and health risk functions, we assess ship-related PM2.5 pollution impacts in 2020 with and without the use of low-sulphur fuels. Cleaner marine fuels will reduce ship-related premature mortality and morbidity by 34 and 54%, respectively, representing a ~ 2.6% global reduction in PM2.5 cardiovascular and lung cancer deaths and a ~3.6% global reduction in childhood asthma. Despite these reductions, low-sulphur marine fuels will still account for ~250k deaths and ~6.4 M childhood asthma cases annually, and more stringent standards beyond 2020 may provide additional health benefits. Lower sulphur fuels also reduce radiative cooling from ship aerosols by ~80%, equating to a ~3% increase in current estimates of total anthropogenic forcing. Therefore, stronger international shipping policies may need to achieve climate and health targets by jointly reducing greenhouse gases and air pollution.

Risk assessment of bilge water discharges in two Baltic shipping lanes.

Environmental concentrations and effects of bilge water contaminants in two Baltic Sea areas were estimated from modelling of discharge rates and analytical data on bilge water from seven ships. Biodegradation of bilge water oil was accounted for and annual water concentrations were estimated to peak in late spring, which coincides with the beginning of a period with extensive biological activities in the sea. Concentrations on bilge water metals were calculated both as water concentrations and as the annual contribution of metals to sediments. The predicted bilge water concentrations of oil and metal in the marine environment were estimated to be 4 to 8 orders of magnitude lower than reported toxic concentrations. However, available toxicity data are based on short term exposure and there is to date limited information on toxic effects of the small but chronically elevated contaminant concentrations derived from bilge water discharge and other operational shipping activities.

Costs and benefits of low-sulphur fuel standard for Baltic Sea shipping.

The maximum allowable fuel sulphur content for shipping in the Baltic Sea dropped from 1%S to 0.1%S in 1 January 2015. We provide a cost-benefit analysis of the sulphur reduction policy in the Baltic Sea Sulphur Emission Control Area (SECA). We calculated the abatement costs based on shipowners' optimal decision-making in choosing between low-sulphur fuel and a sulphur scrubber, and the benefits were modelled through a high-resolution impact pathway analysis, which took into account the formation and dispersion of the emissions, and considered the positive health impacts resulting from lowered ambient PM2.5 concentrations. Our basic result indicates that for the Baltic Sea only, the latest sulphur regulation is not cost-effective. The expected annual cost is roughly €465 M and benefit 2200 saved Disability Adjusted Life-Years (DALYs) or monetized €105 M. Based on our sensitivity analysis, the benefits yet have a potential to exceed the costs. The analysis neither takes into account the acidifying impact of sulphur nor the impact North Sea shipping has on the cost-benefit ratio. Lastly, a similar approach is found highly recommendable to study the implications of the upcoming Tier III NOx standard for shipping.

A comprehensive inventory of the ship traffic exhaust emissions in the Baltic Sea from 2006 to 2009.

This study addresses the exhaust emissions of CO2, NO(x), SO(x), CO, and PM(2.5) originated from Baltic Sea shipping in 2006-2009. Numerical results have been computed using the Ship Traffic Emissions Assessment Model. This model is based on the messages of the automatic identification system (AIS), which enable the positioning of ships with a high spatial resolution. The NO(x) emissions in 2009 were approximately 7 % higher than in 2006, despite the economic recession. However, the SO(x) emissions in 2009 were approximately 14 % lower, when compared to those in 2006, mainly caused by the fuel requirements of the SO(x) emission control area (SECA) which became effective in May 2006, but affected also by changes in ship activity. Results are presented on the differential geographic distribution of shipping emissions before (Jan-April 2006) and after (Jan-April 2009) the SECA regulations. The predicted NO(x) emissions in 2009 substantially exceeded the emissions in 2006 along major ship routes and at numerous harbors, mostly due to the continuous increase in the number of small vessels that use AIS transmitters. Although the SO(x) emissions have been reduced in 2009 in most major ship routes, these have increased in the vicinity of some harbors and on some densely trafficked routes. A seasonal variation of emissions is also presented, as well as the distribution of emissions in terms of vessel flag state, type, and weight.