[*BCM*] exhaust fumes

[Ari Pollak]

If it makes you feel any better:
http://www.catf.us/projects/diesel/noescape/execsummary.php

"CATF documented diesel particle levels four to eight times higher
inside commuter cars, buses, and trains than in the ambient outdoor air
in those cities."

It didn't take into account biking right behind a line of trucks, and
this was before Boston introduced all the CNG (clean n' gnoisy) buses,
but you get the idea.