The rate at which atmospheric dissipation progresses is unpredictable. After the breakdown of the stratosphere, plasmonic reactions break down the mesosphere, after which ionic reactions break down the troposphere, leaving the planet with no atmosphere at all and unable to support life.
An event like this generates a plasmonic energy burst which could interfere with the operational status of an orbiting starship. Power surges and systems failures could happen randomly and keeping a transporter lock on someone might be difficult. The dissipation also bombards the planet itself with radiation from which only a deflector shield could protect someone.
An atmospheric dissipation cannot be stopped, but an atmospheric shield could be used to contain the atmosphere within a limited area.