The huge poster uses nanotechnology to eat up pollution. It was created by scientist Tony Ryan, and the poet, Simon Armitage.
The two are both professors at the University of Sheffield and their creation can absorb poisonous compounds from around 20 cars each day if placed by a busy road.
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They came up with the idea to highlight one possible way to cut disease and save lives by taking poisonous compounds from the air in towns and cities.
How does it work exactly?
The 10m x 20m poster is covered with microscopic, pollution-eating nanoparticles of titanium dioxide. When the light hits them, they react with oxygen and wash the pollution out of the air.
It will eat up things called nitrogen oxides which are not visible but have been linked to breathing problems including asthma.
Professor Ryan said: "If every banner, flag or advertising poster in the country did this, we'd have much better air quality. It would add less than £100 to the cost of a poster and would turn advertisements into catalysts in more ways than one."
Simon Armitage, who is a professor of poetry at the university, has written a poem to go on the poster, titled, ‘In praise of air’.
The poster will be on display in Sheffield next year.
The poem for the poster, by Simon Armitage
I write in praise of air. I was six or five
when a conjurer opened my knotted fist
and I held in my palm the whole of the sky.
I've carried it with me ever since.
Let air be a major god, its being
and touch, its breast-milk always tilted
to the lips. Both dragonfly and Boeing
dangle in its see-through nothingness…
Among the jumbled bric-a-brac I keep
a padlocked treasure-chest of empty space
and on days when thoughts are fuddled with smog
or civilization crosses the street
with a white handkerchief over its mouth
and cars blow kisses to our lips from theirs
I turn the key, throw back the lid, breathe deep.
My first word, everyone's first word, was air.