Neither pleasant nor foul-smelling, and in no way overwhelming: this is how researchers sum up the smell they are calling “olfactory white”.

The smell was uncovered during experiments that mixed aroma molecules from across the scent spectrum. Even if two mixtures had no components in common, they tended towards having a similar scent as more aromas were added. By the time they contained about 30 components, most mixtures smelled alike^{http://www.pnas.org/cgi/doi/10.1073/pnas.1208110109 (2012)." id="ref-link-1" href="http://www.nature.com/news/the-whiff-of-white-could-hide-strong-odours-1.11846#b1">1}, and could mask other distinctive smells.