Just how polluted is it in, say, Iraq? Well, as someone who has spent more time there than my lungs are comfortable with, a lot. But such anecdotal evidence isn't really that scientifically interesting.
For years it's been tough to measure particulate pollution in places where there aren't ground based sensors, and satellites haven't been able to pick up small particulate matter (really small stuff that can bypass your body's defenses and lodge in your lungs). But now some researchers have combined satellite data and have produced this map of particulate pollution from 2001-2006 across the world.
Global satellite-derived map of PM2.5 averaged over 2001-2006. Credit: Dalhousie University, Aaron van Donkelaar
And yep, Iraq is really polluted.