Alt Fuel Ammonia Carries Negative Health Impacts Without Emissions Control

Shipping: exhaust issues. File Image / Pixabay.

Ammonia will need tighter emissions rules for the alternative bunker fuel to have a positive impact on air quality, new research has found.

The study called Climate and air quality impact of using ammonia as an alternative shipping fuel is published as an environmental research letter by IOP Science

Its findings suggest that "while switching to ammonia fuel would reduce tailpipe greenhouse gas emissions from shipping, stringent ammonia emission control is required to mitigate the potential adverse effects on air quality".

This puts the focus "on the technology and policy choices", according to the paper.

"If tuned to balance nitrogen oxides (NOx) and ammonia (NH3) concentration from engine exhaust to allow simultaneous reduction of NOx and NH3 emissions using well-optimized exhaust post-treatment systems with highly efficient combustion modes, deployment of ammonia combustion technology can lead to net health benefits by reducing both ozone (O3) and particulate (PM2.5) levels.

" If the engines are tuned to have lower NOx emissions than NH3–H2 combustion, which is more compatible with current NOx –focused regulatory framework, the unburnt NH3 emission, if unmitigated, can lead to large increases in PM2.5.

"Imposing NH3 emission regulation over current ECA only mitigates 7% of the increases in annual PM2.5-related mortalities from pure NH3 engines."

East Asia is not currently part of any ECAs so the region can expect "the largest negative impacts".

Extending stringent control of NOx and NH3 emissions to the globe would provides substantial air quality benefits, the research suggest.

For research paper, click here.