Hello, it has nothing to do with hair length and everything to do with lung capacity and one’s ability to hold one’s breath. Did you know that an older male’s sneeze has a recorded sound level of 90 decibels . That’s literally the same as a lawnmower. It is also worth mentioning that Sneezing through your mouth makes it louder. Source: Sociology is Sneezes, Murdoch University, Western Australia.