Why You Should Never Jog Behind Somebody

Now that the government has allowed outdoor exercise with the condition that people observe physical distancing and wear face masks, it is worth noting that those who run without facemasks could be spreading aerosols farther than the two-meter physical distance recommended by authorities.
The following simulation shows how aerosol from the mouth spreads when a person is jogging.
The faster you run, the longer your aerosol contours are.

Bert Blocken, a professor of civil engineering at the Eindhoven University of Technology in the Netherlands, warned that respiratory droplets from runners and cyclists can spread farther than the two-meter physical distance recommended by public health officials.
Based on the results of the simulations, the scientist advises the following buffer distances for people exercising outdoors:
- five meters for walking in the same direction
- 10 meters running and slow biking in the same direction
- 20 meters for hard biking in the same direction
Watch these other simulations on how human aerosols spread in different environments.
How Aerosols Spread When Talking
How Aerosols Spread on a Plane, Bus, or Train