RLAF and LAF Diff

what is difference b/w RLAFand LAF?

RLAF- 1. Air flow turbulent
2.Protect material and man
3.Recirculated air
LAF-1 air flow parrelel
2.Air flow once
3 protect material only

kindly explain it

Why RLAF is used for sampling / dispensing of R.M. What happens if we use LAF ?