The Ideal Cycling Speed Is 8 to 9 MPH, Says Science
That’s the alleged “sweet spot” to avoid inhaling too much pollution.
If you biked to work today at any speed other than 8 mph (for women) or 9 mph (for men), you did it wrong. To put that in perspective, those are roughly the top speeds of a house mouse and a pig, respectively.
Also, if you walked at a gait under 2.5 mph (both sexes), you messed up majorly.