No, this isn’t an indictment of postwar architecture: It’s a reminder that unlike prewar buildings--with their windowed bathrooms and kitchens, and non-hermetically sealed construction--postwar air quality relies largely on a functional rooftop ventilation system that sucks stale air from windowless bathrooms, kitchens, and common areas.
In theory, these air ventilation systems do an okay job. But the reality is that accumulated grime, poor maintenance and shoddy renovations can cripple their effectiveness and leave you gasping in the wake of your roasted Brussels sprouts.
To non-scientifically check whether your apartment is breathing properly, hold a tissue up to the wall or ceiling vent and let go.
If it stays there when you pull your hand away, that's a good sign, says Maria Vizzi, the president of Indoor Environmental Solutions, which helps buildings diagnose ventilation issues and, if possible, improve indoor air quality.
“Most of the time, the tissue drops to the floor or, worse, is blown back out,” says Vizzi.
The problem could be accumulated soot and debris in the rooftop fan units--or the common air shaft shared by you and your neighbors.
“Sometimes we see a huge amount of debris left behind from construction sitting in the in the air vents, which are normally at least 12 x 12 inches wide,” says Vizzi, whose company snakes a video inspection camera through the ventilation shafts to find blockages.
“In addition to accumulated soot, we’ll see concrete, newspaper, beer cans, pieces of sheet rock and broken wood—things that clearly should have been disposed in the trash.”
Most of Vizzi's customers do the cleaning every five years, and the video inspection system commonly produces a shock-and-awe reaction.
"People are amazed they were breathing all of that soot for all these years," she says, and not only does the air feel less heavy post-cleaning, but odors don't linger like they used to.
A comprehensive building-wide air ventilation inspection, cleaning, and sanitizing costs between $5,000-50,000.
“The price really depends on the how many apartments there are and whether we're cleaning the whole ventilation system or just a portion at a time," explains Vizzi. The number of apartment lines also affects price: "Each line typically has its own roof fan and most of the dirt winds up residing there."