Wall plants aren't just for decoration; they can improve city air, but not the way you think, so traffic releases tons of pollutants into the air, including tiny particles that are bad for our health, and plants can remove some of those particles. They can absorb particles through the cells in their leaves, but the main way they help us is through dry deposition; that's when particles land on vegetation, taking them out of circulation for a bit. Another tool plants have up their leaves is dispersion, where plants act as a physical barrier, so pollutants don't travel straight from cars to your nose; instead, they swirl around plant leaves first and float away from you, decreasing your exposure trees are definitely the go-to but if you don't have the space, a 100 square centimeter green wall can do the trick.