Ventilation filter

FIG. 1 is a top, front and right-side perspective view of a ventilation filter showing our new design;

FIG. 2 is a bottom, rear and right-side perspective view thereof;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a rear elevation view thereof;

FIG. 5 is a left-side elevation view thereof;

FIG. 6 is a right-side elevation view thereof;

FIG. 7 is a top plan view thereof;

FIG. 8 is a bottom plan view thereof; and,

FIG. 9 is a perspective view of the ventilation filter shown in a state of use.

The broken lines shown in the figures are for the purpose of illustrating portions of the ventilation filter and form no part of the claimed design. The broken lines shown in FIG. 9 are for the purpose of illustrating environmental structure and form no part of the claimed design.