Health and economic impacts of improved air quality from transitioning global shipping energy to hydrogen.

Hydrogen energy is critical for decarbonizing the hard-to-electrify shipping sector and improving air quality. However, the associated health and economic co-benefits remain unclear. Here we assess the health and economic impacts of feasible hydrogen transition scenarios in global shipping using an integrated emission-air quality-health modeling framework. Our results show that hydrogen adoption could avert approximately 129,500 (95% confidence interval: 68,300-202,200) premature mortalities annually-75% attributable to ozone (O3) concentration reduction and 25% attributable to fine particulate matter (PM2.5) decline-with the greatest O3-attributable health gains in Southern Asia and PM2.5-attributable gains in Eastern Asia. These health benefits are estimated to save an economic cost of approximately US$306 billion (US$146-488 billion), with India, Japan and the United States of America receiving the largest economic benefit. The findings highlight the potential of hydrogen-based shipping decarbonization to deliver substantial public health and economic co-benefits.