'This is the air we breathe ... ' are posters designed for raising awareness. They present continuous feedback on our urban environment and the effects of traffic. Using flock printing, a dirt-absorbing text or pattern is printed on a less dirt-absorbing surface in order to create a slow but direct response to pollution. Drivers are reminded of their impact on the city, which is also visible to others passing by. This project embraces complexity, making a problematic and abstract issue local and tangible.