Chemical quench level

A chemical quench level is where a reaction time equals the atmospheric transport time. Above it, transport is faster and carries an approximately fixed deeper abundance faster than local chemistry can restore equilibrium.

Carbon monoxide–methane quenching freezes the CO-to-CH4 abundance ratio near the level where their interconversion time first exceeds the vertical mixing time.

Nitrogen–ammonia quenching similarly preserves a deeper N2-to-NH3 ratio above the level where chemical conversion becomes slower than atmospheric mixing.