New Study Suggests an HFO Ban Would be "Less Beneficial than Expected" and PM Scrubbers Give Greater Health Benefits Than Sulfur Caps

Scientists lead by a team in Germany say SOx might not be the biggest problem when it comes to the impact on human health.

A new study has found that mandating particulate matter (PM) scrubbers, rather than putting a cap on the sulfur content of marine fuel, would be a more effective way to protect human health from the adverse effects of ship emissions.

The research was carried out by scientists of Helmholtz Zentrum München and the University of Rostock in cooperation with the University of Luxembourg, the Max Delbrück Center for Molecular Medicine, the Karlsruhe Institute of Technology, and the University of Eastern Finland, and was recently published in the journal PLOS ONE.

Their study built on earlier work that showed exposure to emissions of PM from both HFO and distillates adversely affects human lung cells, such as causing inflammation linked to the development of interstitial lung diseases.

The latest study found that a particular cell type known as macrophages are not only influenced by the exhaust gases, they are much more sensitive to PM than other types of cells, such as the lung's epithelial cell lining.

The concern is that macrophages are an important type of white blood cell that destroy non-healthy cells, and form part of the immune system that protects against, amongst other things, infection.

"Emitted particles both from the heavy fuel oil and from the diesel exhaust had similarly high toxic effects on the macrophages. Surprisingly, the toxic effects leading to cell death are even slightly lower in the heavy fuel oil emissions, although the concentrations of known toxic pollutants in the heavy oil emissions are much higher," said Professor Ralf Zimmermann, who led the study.

"Foregoing the ban of the heavy fuel oil use in coastal shipping, as is currently propagated and partially already implemented via the current fuel-sulfur content regulations, is therefore probably less beneficial than expected for protecting the health of people in coastal areas.

"The simplest and safest way to mitigate these adverse health effects from ship engine emissions would be to introduce efficient particle reducing measures such as exhaust gas scrubbers and particle filters. These would precipitate the harmful fine particles from the emissions and thus reduce the adverse health effects, irrespective of the fuel used. Since such measures are generally not implemented on a voluntary basis, in our view there is an urgent need for action by policy makers in government and by national and European regulatory authorities."

The findings come just a few months ahead of an expected IMO decision on whether a new 0.50 percent global sulfur cap will come into force in 2020, or delayed until 2025 - a move that will likely see a significant proportion of OGVs switch to burning distillates for compliance.