A Chinese artist just spent 100 days walking the streets of Beijing with a vacuum cleaner, and has made a brick from the city's polluted air.

The artist, who calls himself Nut Brother (坚果兄弟), walked the city's streets for about four hours each day, pushing a large, 1,000-watt industrial vacuum cleaner while holding its nozzle in the air.

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And he's made a brick from the dust and smog collected — a symbol of the city's infamous pollution that has made face masks a common sight on its streets. On Monday, the brick was created at a brick factory, that mixed the vacuumed dust with clay.

Nut Brother told Mashable he was often mistaken for an air quality surveyor or cleaner by passers-by, who thought that it was "cool" for the city to have employed people to monitor and clean the air.

He said he hasn't gone for any health checks after his 100-day jaunt, but said his body feels okay, if a little "numb", but didn't elaborate on where he felt numb.

Several commenters on Nut Brother's Weibo account criticized him for mixing the dirt with clay, saying that it exaggerates the amount of dirt collected. But his work is getting noticed across various local media outlets, which are lauding the message behind his project.

Of his project, he said (translated from Chinese): "The day we exhaust all of the Earth's resources, we will ourselves turn into dust."

Nut Brother's project is especially timely, given that Beijing on Monday upgraded its air pollution warning alert to "orange" — the highest reading in 13 months. Beijing has suffered from air pollution for years, in large part due to massive coal burning in industrial cities up North. An estimated 4,000 people die each day due to air pollution, say physicists.

The artist was a former copywriter in Shenzhen till he decided to give it up and move to Beijing in 2008.

Prior to this brick project, he bought a (presumably deceased) dog from Yulin — the city which holds an annual festival where dogs are slaughtered and sold as meat — and cremated it. He filled 1,000 blue balloons with the ashes and floated them up in the sky. When the balloons burst after floating too high in the sky, they scattered the ash, a symbol of sending the dog up to "heaven," according to the artist.

Updated Dec 1, 2015 10:25 PM EST with comments from the artist, Nut Brother.

[h/t Quartz]