The ornamental design for an airtreatmentappliance, as shown and described.
FIG. 1 is a top isometric view of an air treatment appliance, showing our new design.
FIG. 2 is a bottom isometric view thereof.
FIG. 3 is a front elevational view thereof.
FIG. 4 is a rear elevational view thereof.
FIG. 5 is a left side elevational view thereof.
FIG. 6 is a right side elevational view thereof.
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a bottom plan view thereof.
In the drawings, stippling represents the three-dimensional contours of the design, and is not intended to indicate surface decoration. The broken lines shown in the drawings depict portions of the air treatment appliance that form no part of the claimed design.