The international kilogram conundrum

on one page: http://www.latimes.com/news/nationworld/nation/la-sci-kilogr...

A nonissue. Some gain weight as dust settles somewhere on the housing; others lose weight due to erosion during handling. It's a grain of salt difference.

Additionally, weight differs slightly depending where on the planet you are as Earth bulges around the equator some 80 miles more than around the poles. The farther you are from the center, the more the pull of gravity diminishes. Increasing elevation also has this effect.