The jeepney is typically open, meaning that it has no doors or windows, just holes for people to slip into and breathe out of. Unfortunately, when you ride the vehicle throughout major metropolitan areas, you get a face full of exhaust almost every time.
While funny because it's true, it's also a bit unfair, because that isn't the case a hundred percent of the time. What is true 100% of the time is the horrible exhaust coming from the back of the vehicle, caused by the archaic diesel engine it carries. What's even more horrible about it is that, when the jeepney is moving, it sucks the pollution it exhales right back in, and the riders appreciate this all the more because the jeepney is completely open, allowing more of the contaminated air to flow in. The faster the jeepney goes, the more black air it sucks back in. This is caused by something called drag force.
WHAT TO DO
You can read about the science behind it in more detail if you like, but the point is that sitting near the tail end of the jeepney is extraordinarily bad for your health, especially if you ride it regularly. If you can, ride up front with the driver, or sit as close to him as you possibly can. Much of the exhaust would have already dissipated by then, leaving you much cleaner air to breathe in. I assure you, this is much better for you in the long run than having to consider wading through a bunch of seated people when you get to your stop.
Got any more health-related tips regarding jeepney riding or have questions about turbulent flow? Leave a comment below and share your thoughts!