MIT study highlights health risks of switching from diesel to ammonia fuel in maritime shipping

A recent study by MIT researchers has revealed that while switching maritime shipping fuels from diesel to ammonia could reduce carbon emissions, it also poses significant health risks due to its impact on air quality.

The study, published in the Environmental Research Letters journal, warns that without stringent new emissions regulations, the use of ammonia as a maritime fuel could lead to increased ozone pollution and severe health consequences.

The key findings of the study are as follows:

• Air quality and health impacts: The report states that the combustion of ammonia generates nitrous oxide (N2O), a potent greenhouse gas, and nitrogen oxides (NOx), which contribute to the formation of fine particulate matter. These pollutants are linked to serious health issues, including heart attacks, strokes, and asthma.
• Premature deaths: The report finds that under current regulations, switching to ammonia fuel could result in up to 600,000 additional premature deaths annually. However, with advanced engine technology and stricter emissions controls, this number could be significantly reduced.
• Technological and policy scenarios: The study assessed two types of ship engines and three regulatory scenarios. The first engine burns pure ammonia, while the second mixes ammonia with hydrogen to enhance combustion and reduce emissions. Regulatory scenarios ranged from current NOx limits to comprehensive global restrictions on ammonia and NOx emissions.
• Geographical disparities: According to the report, the negative health impacts of ammonia fuel would be most severe in East Asia, where shipping volumes are highest and air quality regulations are less stringent.

In addition to this, the study refers to two significant Implications for the shipping industry.

A need for holistic approaches

Firstly, the report stresses the necessity of considering both environmental and public health impacts when evaluating alternative fuels.

“Not all climate solutions are created equal,” noted Anthony Wong, the study’s lead author.

Policy recommendations

Moreover, the researchers emphasise the importance of developing policies in tandem with new technologies to ensure that the shift to cleaner fuels like ammonia does not compromise public health.

“There is a potential for ammonia in shipping to be beneficial for both climate and air quality, but that requires appropriate regulations,” said co-author Noelle Selin.