Short answer
Some products sold as “dustproof insect screens” are just more tightly woven mesh. What really makes the difference is the type with a nanofiber layer in the middle: window filter.
The difference between tight mesh and nanofiber
| Tightly woven mesh | Nanofiber window filter | |
|---|---|---|
| Flies and mosquitoes | ✓ Stops | ✓ Stops |
| Tiny insects | Partly | ✓ Stops |
| Fine dust | ✗ Gets through | ✓ Holds back most |
| Pollen | ✗ Gets through | ✓ Holds back |
| Airflow | ✓ Yes | ✓ Yes |
Made to measure: hook-and-loop or roll

