The University of Belgrade’s Institute for Multidisciplinary Research invented an urban photo-bioreactor. Liquid 3 cleans the air and serves as a bench in the Belgrade city centre.
It's a tank filled with microalgae, a solar panel on the top generates electricity for USB charging ports for citizens and a pump that pumps air into the tank where the algae process the CO² and produce Oxygen.
https://balkangreenenergynews.com/liquid-tree-to-combat-air-pollution-in-belgrade/
according to the article the tank must be connected to grid power to keep temperature, must be completely flushed out, cleaned and replaced every month, and is equivalent to one tree
Isn't technology wonderful? Just imagine how many jobs this Liquid Tree® creates, compared to obsolete "trees."