The CDC publishes the BMBL, which pretty much is THE biolab safety standard. Here is what they say (BMBL 5 sect IV BSL2) about BSL2 lab practices and aerosols: "all procedures in which infectious aerosols or splashes may be created are conducted in BSCs or other physical containment equipment." BSL2 rated work is with those organisms which are known to be infectious through ingestion, or contact with mucous membranes (eyes, nose), or breaks in the skin. It doesn't include organisms known to be infectious through respiratory exposure (such as tuberculosis), as those are RG3 materials which require BSL3 lab facilities and practices, which are more restrictive...

Maybe you're familiar with (or can recite whole passages in your sleep!) the BMBL, but here is a link

best,

Margaret