Zou Yi. [Photo by Zou Hong/China Daily]

"Rich or poor, we all breathe the same air. We all win or lose together."

Zou began the project after smog choked Beijing's skies for nearly two weeks in January 2013, a period internationally known as the "airpocalypse".

His followers reacted strongly when he tweeted a grid of the first 64 photos.

"Friends said you truly get a clear idea of air pollution at a glance. They encouraged me to continue."

His family and friends snap the photos for him if he's out of Beijing.

He'd planned to stop after his 365th picture. But he changed his mind after he posted it.

Followers' enthusiasm propelled his determination.

"People are used to getting my photos daily and push me if I tweet late," Zou says.

"We've had a lot of discussions. I feel yi mu liao ran isn't a personal project anymore but has become a duty."

He has enhanced the tweets by including commentary with the tower photos under the pseudonym "#No 1 Bus# Driver".