The maritime shipping industry accounts for roughly 3% of global carbon dioxide emissions annually and ammonia has the potential to reduce this as a low-carbon fuel, but a new MIT study indicates safety concerns with air quality when switching ship fuel from diesel to ammonia.
The study, led by Anthony Wong and funded by the MIT Climate and Sustainability Consortium, highlighted that nitrous oxide, a greenhouse gas that is 300 times more powerful than carbon dioxide, is created when ammonia is combusted. Nitrogen in the form of nitrogen oxides and unburnt ammonia may also leak, which forms fine particulate matter in the atmosphere that can cause health problems such as heart attacks, strokes, and asthma.
Under current legislation, the study indicates that switching the global fleet of ships to ammonia fuel from diesel could have a net impact of up to 600,000 additional premature deaths each year due to air quality concerns. With stronger regulations and cleaner engine technology, however, the study found that switching to ammonia could lead to roughly 66,000 fewer deaths than currently caused by maritime shipping emissions, along with a lower impact on global warming.
“The results of this study show the importance of developing policies alongside new technologies,” said Noelle Selin, one of the authors. “There is a potential for ammonia in shipping to be beneficial for both climate and air quality, but that requires that regulations be designed to address the entire range of potential impacts, including both climate and air quality.”