Work in front of a laminar flow hood that is filtering .02 microns you will minimize most of the airboune issues that occur in normal situations. However, in order to guarentee proper air filtration you will need another laminar flow hood filtering .2 microns taking air from your external air source to your clean room.
Figure A. ( left) The layers of filtration required for sterile technique depicted above. HEPA is an acronym for high efficiency particulate air.
Figure B. ( above right) The key to sterile air flow is pre filtering with a basic screen before it passes the hepa filter. The ambient air in the room should also be filtered with the same system.
a barrier of positive pressure in the work space. ( when you pump air into the room that is also hepa filtered you will notice the air pushes at the door busting at the seems with fresh filtered air. this why it is impertive the entire space is a non poruous surface and you can wipe the walls down).