The phrase "dark air" is correct and usable in written English.
It can be used to describe an atmosphere that feels heavy, oppressive, or foreboding, often in a metaphorical sense.
Example: "As the storm approached, a sense of dark air enveloped the town, making everyone uneasy."
Alternatives: "gloomy atmosphere" or "heavy air."
Incense filled the dark air.
The dark air coming in my open window is sweet, smelling of night, garbage, and cats.
But others seemed moved by whatever lingered in the cold, dark air.
Tall summits, golden in the level light, rose like islands over the lake of dark air below.
Thankfully in the Dark Air pollution may be bad, but for an astronomer, light pollution can be much worse.
John, too busy juggling camera, thermal imaging cellphone and digital recorder to notice, goes right on taking pictures of the dark air around us.
We had left behind the convivial planet where my cousins lived, and we were plummeting south toward a quiet, dark, air-conditioned house in which I didn't even recognize loneliness as loneliness, it was so familiar to me.
[cue boos from the pro-bulls crowd. The stadium goes dark, air-raid lights swirl round the arena, and someone a stadium attendent turns the volume on the pumping nu-metal soundtrack (sorry, I'm too old to know what it is) to 11.
Moist snuff features a blend of fire-cured and dark air-cured tobaccos, and is manufactured through a fermentation process in closed vessels during a period of several weeks, with pH and temperature monitoring [47].
Or hiding out in a dark air-conditioned room as I did last week.
When I discovered after school activities that involved hanging out in dark, air-conditioned places playing make-believe (What's up, theater nerds!) I gave up organized athletic pursuits altogether.
