This all started with the challenge of a friend to turn my ideas into reality. I did.

I took the idea from living abroad. Everyone hung their laundry to dry, but rain would bring the smog down onto your clothes and would clean the air. Perhaps we can do the same, but without putting the dirt on our laundry.

All the pieces (except the finger guard) can be printed on a 15x15x15 cm printer.
There are 3 versions in the pictures:

Version #1 - The concept: By making the fan blade skeleton out of diagonally oriented bars, it could be 3D printed with a cheap printer. I sewed on some quick-dry (water-wicking) fabric with the stretchable direction being horizontal so that it would stretch over the fan blade easily. I used a 3D pen to put it together

Version #2 - The build: To make it more friendly to being put together, I made tabs and holes for screws and bolts. It's still a good idea to use a heat gun to seal the joints (or to make a gasket out of flexible filament) so that it doesn't leak out the sides.

Version #3 - The mobility: Both versions 1 and 2 broke being dropped on the floor. While this isn't meant to be thrown around, I still wanted it to be able to hold up to ... life, so I made the fan blades thicker and streamlined the design for attaching the blades and motor. I added the finger guard with the back open for the motor and a front cover with space for a logo if I wanted to make it large scale. I also made a base which could fit on a flat bottom or have rails to set up an array. Even without an array, it could be set up on a common bucket found at home improvement stores.

The files are for version #3. The bearing holder is separate so that you can modify the size to fit whatever style bearing you have.

Bonus notes:
-There is a dimple on the bottom the driver. This is where you can drill a small hole to attach your motor. The top has an open hole. When you add the bearing holder and bearing, you'll still have a hole large enough for a tube. This is the water inlet. If you use a large enough bearing, you can add strength (for holding up the fan) by using a metal straw or car brake hose as your attachment. Just be careful not to make the tube too small or your water pump will need more strength.

-I didn't get into any arduino projects with this, but I did design it with customization in mind. I would love to see what the community can come up with.

-By using PLA, I lowered the cost and made it easily recyclable. I would love to see entire cities transformed by common people just looking for better air. Imagine if cities were to subsidize local people solving issues locally in an environmentally friendly way!