I would say that, because of the short and concentrated dispersion of the "dust", it was probably a pepper ball that hit him ...
... but, whatever it was, that sure was funny, I don't care who you are ...
Maybe? Check the vid link below, go to 0:09 and settings at 1/4 speed. There’s a large puff of smoke upon impact.
https://www.youtube.com/watch?v=uHti9XctDms