"Strange smell," said Cedar Rapids Resident Bo Johnson. "It's smelly. It's stinky."

"It was nauseating," said Tara Farris. "It was really bad."

"It just smelled awful. I thought somebody had passed gas," said Trenton Richard. "I don't know what it was but it was the most disgusting thing ever."

It's the sniff without a source that has people in Cedar Rapids on edge.

"It smells like dirty diapers," said Dawn Pata. "I work at Waypoint, I'm in childcare, so yeah I know that smell."

"I think they really need to find out what this smell is and clean it up quickly because it's going to make me gag," said Johnson.

People are saying it's coming from all directions of town. But the question is, what is the rancid reek?

Linn County Air Quality Supervisor Shane Dodge says the smelly secret is a potpourri from the wind.

"Everybody likes to blame the wastewater treatment plant, which was a large contributing factor in this odor incident but also anybody else that's in that river valley that emits odors," said Dodge. "So, if there's manufacturers, maybe compost facilities or whatever it might be."