OK, in that case 1% of the ocean weighs 1.33×10^19 kilograms, the atmosphere weighs 5.1441×10^18 kilograms.

If you actually did this you would increase the atmosphere to 10 times it's current size - and most of that would be oxygen, unlike the current mostly nitrogen. Most of which would probably escape to space.

You'd have to find something to do with the hydrogen though, if you released it it would just recombine with the oxygen and make water again.