6.1.5 (HL)—Atmosphere as dynamic system

A stable concentration can result from opposing processes continuing at similar rates; it is not a static layer.

Air movement and radiative balance redistribute energy physically. UV splits O₂ and oxygen atoms combine with O₂ to form ozone; ozone is also destroyed, creating a dynamic equilibrium.

Ozone concentration may stay roughly stable while formation and destruction both continue.

A sustained change in one rate, such as extra chemical loss, without an equal compensating process.

Stable amount does not mean no reactions or no movement.