Unfortunately, the driver of the second car in the line across the street opposite the camera car, a little Mazda 3, appears to not hear the approaching wail. He drives around the first car, which stopped in the process of making a left turn, so we guess that's why the Mazda driver doesn't think twice as he heads straight into the intersection.

Diesel exhaust, for example, is a carcinogen, and in older firehouses — Boston’s date from the 1800s to 1980s — the truck bays are near the living quarters. Also, the design of the buildings is such that air flows easily through doorways and the hole in the floor for the fire pole, Sparer said.

"[Fighting fires] is very important, however, a lot of firefighters actually don’t spend the majority of their shifts fighting fires," Sparer said. "They respond to car accidents or are at the fire station, where there might be other kinds of exposures that haven’t been looked at."

One of those shows called “Tiny House Big Living” will feature the couple’s latest housing project—a tiny firehouse.

The couple says their unconventional lifestyle helps them give back.