"Nearly all controlled ozone-depleting substances have been phased out, and the ozone layer is expected to return towards its 1980 condition over the coming decades. Low-Earth orbit is now creating a different source of reactive material. Short-lived satellites vaporise metal as they reenter. Aluminium reacts with oxygen during that destruction, forming particles of aluminium oxide. The concern is scientifically plausible, but its scale remains unsettled."

https://spacedaily.com/t-satellite-reentry-aluminium-oxide-nanoparticles-ozone/