Air Pollution unfiltered

I was revising for my SWE 316 Air Pollution and Control Engineering endsem exam today on my way in the 64 bus, sitting by the window.

I ran my hand over the page and my fingers felt granules on the paper and not the smooth paper.

That's certainly some PM in the air then for sure, if I can literally feel it with my fingers.

Kinda aced the paper though, writing about the NAAQS and the health effects of air pollution.