Press release archive: 2018

Cleaner ship fuels benefit health, but affect climate too

6.2.2018 18:05

Marine shipping fuels will get a whole lot cleaner in 2020 when a regulation by the International Maritime Organization (IMO) requires fuels to contain 80-86 percent less sulphur. Study finds cleaner ship fuels will reduce childhood asthma by 3.6 percent globally but it will also accelerate climate change.

Photo: Hannu Manninen

Photo: Hannu Manninen

The new IMO rule will decrease the allowable amount of sulphur in fuel oil from 3.5 percent to 0.5 percent, a reduction from 35,000 parts per million (ppm) to 5,000 ppm. This is the most significant improvement in global fuel standards for the shipping industry in 100 years, intended to achieve significant health benefits on a global scale.  Now, a new study in Nature Communications quantifies these health benefits and finds cleaner shipping fuels will result in a 3.6 percent reduction of childhood asthma globally.

The team studied the impacts of sulphur emitted by ships using current marine fuels, which produce air pollution particles that are small enough to be breathed deeply into the lungs and are considered harmful to human health.  Ship air pollution effects are greatest in areas where heavily travelled ship routes exist in, and next to, densely populated communities.  Some key regions include China, Singapore, Panama, Brazil and coastlines of Asia, Africa and South America.

Refining industries will invest in the necessary technology to produce, and shipping will invest to adapt engine systems to use, these cleaner fuels. "Essentially, we document how much health benefit to expect from the 2020 adoption of cleaner ship fuels," said James Corbett, professor of marine science and policy in UD's College of Earth, Ocean, and Environment, and the paper's corresponding author.

Roughly 14 million annual cases of childhood asthma are estimated to be related to global ship pollution using current fuels. The change to cleaner ship fuels will reduce the ship-related childhood asthma cases by half. Additionally, shipping pollution is estimated to contribute to 400,000 premature deaths from lung cancer and cardiovascular disease annually. Using health risk estimates for ships comparable with the World Health Organization totals, ships account for about 3-4 percent of global lung cancer and cardiovascular deaths caused by air pollution.  About one-third of these ship-related cardiovascular disease and lung cancer deaths will be reduced with cleaner fuels.

Public health benefits bring climate tradeoffs

"Researchers used a state-of-the-art model of ship traffic based on satellite records to determine where ship activity was producing emissions", explains FMI researcher Jukka-Pekka Jalkanen.

While the health benefits are clear, the research also quantifies tradeoffs in terms of climate. "Sulphur dioxide emissions from ships create small particles. These sulphur containing particles reflect sunlight and help form brighter clouds, creating a global effect that temporarily diminishes the warming effects of carbon dioxide. The use of cleaner ship fuels will increase the rate of global warming by about 3 percent," said FMI senior researcher Mikhail Sofiev, who led the climate related research. "This means more attention may be needed to reduce greenhouse gases across all sectors of the global economy."

Think of this warming effect like a pot of water boiling on the stove. Adding ice cubes to the boiling water can slow how quickly the water heats up, but it does not stop the heating itself. It's the same with sulphur in the atmosphere.

At the same time, shipping activity is expected to increase with global trade and continue to produce harmful air emissions and greenhouse gases. Despite the upcoming reductions, low-sulphur marine fuels will still account for approximately 250,000 deaths and 6.4 million childhood asthma cases annually, so more stringent standards beyond 2020 may be needed to provide additional health benefits.

The study was led by University of Delaware's and included an international team of researchers from the Finnish Meteorological Institute (FMI), Rochester Institute of Technology (RIT) in New York and Energy and Environmental Research Associates. Study was funded in part by ClimateWorks Foundation, the Academy of Finland, with in-kind support from the Finnish Meteorological Institute and Energy and Environmental Research Associates, LLC.  

More information:

Senior researcher Jukka-Pekka Jalkanen, tel. +358 50 919 5455,

Research professor Mikhail Sofiev, tel. +358 50 529 0578,

Sofiev, M. et al. Nature Communications volume 9, Article number: 406 (2018)