The ornamental design for an airfiltrationdevice, as shown and described.
FIG. 1 is an upper perspective view of an air filtration device showing our new design;
FIG. 2 is a bottom perspective view of the air filtration device;
FIG. 3 is a front view of the air filtration device;
FIG. 4 is a rear view of the air filtration device;
FIG. 5 is a right side view of the air filtration device;
FIG. 6 is a left side view of the air filtration device;
FIG. 7 is a top view of the air filtration device; and,
FIG. 8 is a bottom view of the air filtration device.
The broken lines showing in the figures are included for the purpose of illustrating portions of the air filtration device that form no part of the claimed design.