What penalty does a player incur for removing sand particles from behind their ball while preparing for a putt from the fringe of the green?

When a player removes sand particles from behind their ball while preparing to putt from the fringe of the green, the action incurs a penalty because it violates the rules regarding altering conditions that affect play. According to the Rules of Golf, specifically the areas surrounding the putting green (which includes the fringe), players are not allowed to improve their lie or the conditions affecting their stroke by removing loose impediments that are actually part of the course's natural condition.

In this situation, the sand particles may not be classified as loose impediments, and therefore, removing them violates the rules concerning the integrity of the course. This act is deemed to be a deliberate effort to alter the environment around the ball, which directly affects how the ball will roll during the stroke. Thus, incurring a one-stroke penalty for this infraction is appropriate and aligns with the specific rules governing play on the green and its immediate fringe area.

This penalty intends to maintain fair play and ensure that all players deal with the same course conditions regardless of their action, hence a one-stroke penalty is the correct consequence for this behavior.