Choosing a Pore size The pore size of your syringe filter is determined by the size of the particles you need to filter out of your aqueous solution. Syringe filters for aqueous solutions are available in these pore sizes: 0.05 µm, 0.10 µm, 0.22 µm, 0.45 µm, 0.70 µm, 0.80 µm, 1 µm, 3 µm, 5 µm, and 10 µm.