Laminar flow hood
A laminar flow hood is a small space where with the help of a ventilator and an HEPA filter an almost perfectly sterilized environment can be created. In a good laminar flow hood you can do your cultivation work with barely any risks.
HEPA stands for High Efficiency Particulate Accumulation. These filters clean the air from 99, 97 % of all available particles bigger than 3 micron. If you let air from a ventilator blow through the HEPA, you create a flow of air on the other side of the filter. This air is free of eventual contamination. It also keeps away the air coming from your direction. And this is precisely the air flow which is filled with airborne contamination. Thanks to this filter you can work in an environment as sterile as possible. It's very important that the ventilator has exactly the amount of power needed for the size of HEPA filter that you're using. If the ventilator isn't powerful enough the air flow coming through the filter will be too little to guarantee a sterile space to work in.
A laminar flow hood with a HEPA-filter is an interesting device for the experienced grower who wants to develop his mushroom cultivation. A laminar flow hood is a reasonably expensive investment, but when the mushroom growing hobby becomes out of hand, it's surely worth it.