How long does it take air to travel around the Earth?

My curiosity, really, is how fast airborne pollution can spread. So, let's say I were standing at the equator, and I blew some bubbles. Bubbles that don't pop, right? Generally, how long would it take for them to travel around the earth and come back to me? Would it be the same at other latitudes?

Earth is 24,901.55 miles around at the equator. If the bubble traveled at 3 mph, that would take 345.85485 days. It would be different at other latitudes as long as it traveled straight.

sand storms, volcanoes, etc will put sand or ash all the way around the earth in a short period of time... perhaps within 6 to 14 days. There are air currents high in the atmosphere that travel at 100 to 300 miles per hour.