My best guess would be a group of engineers, in collaboration with the rms(formally rta).
in relation to atmo bovs.
1, would be primarily noise.
2, being part of the intake system, on the pressure side, after the turbo, this is also after the pcv, which vents oil/fuel vapour from the sump.
this contains unburnt hydrocarbons, which are a form of pollution.
might be very small, but it all adds up.
This is the very same reason you have a charcoal canister and fuel tanks are no longer vented.