We have class 100 (ISO class 5) space that's a lot more stringent, but even that is less sensitive than you might expect. Our semicon customers have a bad habit of taking our carefully bagged product out in their uncontrolled warehouse to check the serial numbers, but I'm not aware of any issues that arose from this.
Things get a lot more interesting when you start working with DUV and EUV wavelengths, as now you care about more than dust. We're adding an advanced molecular contamination cleanroom (AMC) where we'll need to start restricting perfume, deodorant, and cigarette use.
There are entry protocols around what you can take in, how you swab it, and so on. Also, specific instructions around how often to go from sitting to standing, clothing materials under your smocks, and everything else.