Suppose I'm in my room with my keyboard, my desktop and my desk. Are these objects losing or gaining atoms every second? Or are they forever stuck with the same number of particles until you scratch, break or pulverize them?

Or suppose, for simplicity's sake, I have a pure gold sphere in my room. Neglecting the presence of dust or oxide layers...would it be losing or gaining atoms over time on account of simply *standing* untouched in one place?