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Limits RegistryThe Antarctic ozone hole reached its largest-ever single-day extent of approximately 29.9 million km² on September 24, 2006 — roughly three and a half times the area of the contiguous United States — as measured by NASA and NOAA satellites. Ozone-hole area has generally trended smaller since the 1987 Montreal Protocol phased out ozone-depleting chemicals, though it still varies significantly year to year with stratospheric weather conditions.
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The Antarctic ozone hole reached its largest-ever single-day extent of approximately 29.9 million km² on September 24, 2006 — roughly three and a half times the area of the contiguous United States — as measured by NASA and NOAA satellites. Ozone-hole area has generally trended smaller since the 1987 Montreal Protocol phased out ozone-depleting chemicals, though it still varies significantly year to year with stratospheric weather conditions.
The greatest single-day area ever measured for the seasonal Antarctic stratospheric ozone hole, per satellite monitoring.
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Limits Registry. LR-LARGEST-OZONE-HOLE. Largest Antarctic ozone hole ever recorded. 2026.