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Why were ozone losses generally greater near the poles than in the tropics?

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ozone depletion — Ozone depletion The Antarctic ozone hole reaches its maximum extent in October of each year. On October 7, 2021, when this image was captured, the Antarctic ozone hole spanned 24.8 million square km (9.6 million square miles).

Ozone losses are significantly greater near the poles than in the tropics primarily due to the unique meteorological conditions of the polar regions, specifically the formation of the circumpolar vortex.1

During the polar winter, this vortex isolates the air over the poles, leading to extremely cold temperatures. These conditions facilitate the formation of polar stratospheric clouds (PSCs). Chemical reactions occurring on the surface of these cloud particles convert relatively stable chlorine-containing molecules into highly reactive forms.1

When sunlight returns to the polar regions in the spring, it triggers the release of reactive chlorine atoms, which then rapidly destroy ozone molecules. Because these specific conditions—extreme cold, isolation by the vortex, and the resulting PSCs—do not occur in the tropics, ozone depletion is far less pronounced in lower latitudes. While chlorine and bromine are the primary agents of destruction globally, the polar environment acts as a catalyst that accelerates this process to a much higher degree.123