# What is the average speed of human sneeze?

I sneeze a lot, at various times and various "volumes", and often wonder about the speed of the sneeze itself, i.e. the speed of the air coming out of the nose while sneezing.

What is the average speed of that, in humans? Are there any records for such a thing?

## 3 Answers

Mainstream understanding is that a sneeze is 100 mph, or ~45 m/s. However, this isn't even close to being true..

A study in 2013 (see link below) was conducted where they investigated the airflow dynamics of sneezing and breathing, and discovered that the highest velocities of a sneeze are around 10 mph, or 4.5 m/s.

...the maximum sneeze velocity derived from these measured distances was 4.5 m/s.

So, about 1/10th the value of what most people believe.. just like the 10% use of our brain misconception, but reversed! (we use 100% of our brain.. not necessarily all at the same time, but we do utilize all parts of our brain)

Airflow Dynamics of Human Jets: Sneezing and Breathing - Potential Sources of Infectious Aerosols

• While this is a good study, my understanding is that they looked at the extent of the propagation of the sneeze 'plume', based on Schlieren imaging of the turbulent flow. It's quite possible that the flow through the nose (which might still be laminar to some extent) has a higher velocity. That wasn't an item of interest in the study (since they were looking at sneezing in its role as propagating an infectious aerosol), but a simple argument from volumetric flow rate necessary to expand the plume suggests that through-nostril velocity should be higher than plume velocity. Commented Jul 26, 2017 at 15:39
• Yes, the air velocity coming out of the nostrils is greater than the plume velocity.. you can safely make this assumption solely by considering Bernoulli's principle, and the fact that airflow outside the nostril has more interaction with it's surrounding atmosphere than it does inside the nostril. Regardless, the difference in velocity would still only be 10-15% at most. To get a more precise idea though, you could consider the rate traveled of sneezed particulate, and account for air resistance, to then derive some kind of initial force and velocity. We're still talking under 20mph though.
– user22020
Commented Jul 26, 2017 at 16:37

## About 35-40mph

According to the Mythbursters who subjected this to their tests showed that their own sneezes went around 35 to 40mph. This is anecdotal since it only has a sample size of two persons, but it at least gives an indication about the speed of a sneeze.

• Mythbusters is absolutely terrible in how they conduct their "experiments", and 99% of the time, its not proper science.Sorry, but this answer is inaccurate.
– user22020
Commented Jul 26, 2017 at 12:40
• @Shadow Wizard I would rather trust a recently published study that was conducted by multiple PhD's and peer-reviewed by a scientific community, than a couple guys on a TV show just looking to entertain. And why would we not know how they measured the speed? It was a TV show, I'm sure they showed it.. and if they didn't, that just even more supports my argument that Mythbusters isn't real science.
– user22020
Commented Jul 26, 2017 at 12:48
• @ShadowWizard Are you serious? The absolute, only difference between velocity and speed is that velocity also describes direction, whereas speed doesn't. That being said, your statement doesn't makes any sense. Please don't try to discuss things that you're not familiar with. And yes, I'm sure they're talking about "actual speed" in the scientific, published study..lol.
– user22020
Commented Jul 26, 2017 at 12:57
• @Charles: While I agree with your point regarding the accuracy of Mythbusters' experiments, I feel obliged to add this xkcd link: xkcd.com/397 Commented Jul 26, 2017 at 21:36
• @tonysdg Haha, it has Richard Feynman. That comic is right on, however, I'm not sure how successful Mythbusters is in actually motivating people to stop watching TV, get off the couch and do their own experiments. Also, to me that comic suggests the argument of what is the bare minimum of an experiment, and what is considered to be just fooling around. I think Mythbusters is a successful TV show because it walks the fine line between those two concepts. +1 to your comment though.
– user22020
Commented Jul 26, 2017 at 22:08

Results seem to vary wildly depending on the methodology. Charles' article on plos.org seems to be serious, and is very complete. Still, looking at an earlier study of Penn State University published by LiveScience, they measured speeds of up to 200 miles per hour.

As mentioned in the article:

"The smaller and lighter particles are less affected by gravity and can stay airborne almost indefinitely as they are caught up in and dispersed by the room's airflow. [...] Some of [these particles] rocket out at speeds greater than 200 miles per hour."

It does not go into details of how the Penn State University experiment was measured, but it clearly shows that you would have to agree on a methodology and which particles' top speed to use to get some consistent results.