Environment & Energy

Pittsburgh 1925, and I've seen many old photos like this. I believe the air was always this bad back in those days. The steel mills were the source of the smoke and smog. Steel mills operated inside the city limits, and surrounding hills caused the smog-bowl effect. The mills burned coal and smoke stacks of the time were not tall enough to channel mill exhaust out of the lower atmosphere.

As a teenager I moved to Pittsburgh in the 1960s and they still had occasional smog-days like this back then. I can remember smog so thick that you couldn't see more than 20 feet, but it would burn off after a couple hours. These days the mills are mostly closed, and the EPA's pollution-prevention regs have completely turned around the air and water quality of Pittsburgh.