Unfortunately it is very much true.
Edit: here’s a more recent source.
This is not hot air though, so the cited source does not apply.
Edit: but it does link to more relevant study towards the end, comparing different means of hand drying.
You’re right and I linked a fairly old study. I’ve edited my comment to add a more recent source.
Findings: Air bacterial counts in close proximity to hand drying were 4.5-fold higher for the jet air dryer (70.7 cfu) compared with the warm air dryer (15.7 cfu) (P=0.001), and 27-fold higher compared with use of paper towels (2.6 cfu) (P<0.001).* Airborne counts were also significantly different during use of towel drying versus warm air dryer (P=0.001). A similar pattern was seen for bacterial counts at 1m away. Visualization experiments demonstrated that the jet air dryer caused the most droplet dispersal.
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