They lead to a higher cylinder charge, resulting in a lower combustion temperature with lower NOx emissions as well as a leaner combustion air ratio and therefore lower particulate emissions. (occup-med.biomedcentral.com)
From our side, I think the number - one move to allow higher compression ratios will be the development of water injection to reduce combustion temperatures — it's all about controlling knock or pre-ignition. (evo.co.uk)
Forced induction motors like octane - the high pressure, high compression, and most importantly high combustion temperatures make you more prone to detonation. (mechanics.stackexchange.com)