An unusually quiet bus ride for the time of day, but you would hear no complaints from me.

What you would hear, however, were intermittent hissing sounds, that seemed to cease each time I looked up. It took multiple attempts of searching for me to determine the sound's origin. I thought,

"It must be the hydraulics of the bus."

Nope; the bus stayed a steady height throughout the ride, and the sound was definitely more focused. The noise sounded again, and I focused my attention towards the front of the bus, spotting a man hunched over with his bag wrapped around his arm, and the hand of his other arm cupping something. Now that I was giving this noise my full attention, I found it to be familiar, thinking...

"Oh, that must be an inhaler."

Wrong again. Although I was immediately satisfied with the answer, I realized the duration of the man's inhalation didn't match the "burst" of an inhaler. Further still, it didn't quite sync up with my memory of my brother's inhaler. Still unable to see beyond the bag, I return to my thoughts:

"Is that a vape pen? You're vaping on the bus? Come on, man..."

In hindsight, I wish he were vaping. The man hunched over again, and I saw a familiar, red straw poking out of the bag, and a stark black nozzle atop a white canister.

It was compressed air. The man had been inhaling compressed air.

Like, a lot. At least for five seconds at a time, every thirty seconds or so. And my commute was fifteen minutes long.

The strangest part about it was, it felt like I was the only one who noticed, as nobody batted an eye. The more likely case: he had been on the bus for quite some time before I was picked up, doing this all the while.