FIG. 1 is a front elevational view of an air purifier showing my new design;
FIG. 2 is a rear elevational view thereof;
FIG. 3 is a left side view thereof;
FIG. 4 is a right side view thereof;
FIG. 5 is a top plan view thereof;
FIG. 6 is a bottom plan view thereof;
FIG. 7 is a top, front and left side perspective view thereof;
FIG. 8 is a bottom, rear and right side perspective view thereof;
FIG. 9 is an enlarged view of portion 9 in FIG. 7; and,
FIG. 10 is an enlarged view of portion 10 in FIG. 7.
The evenly spaced broken lines in the drawings illustrate portions of the air purifier which form no part of the claimed design. The dash-dot broken lines showing the enlargements in FIGS. 7, 9, and 10 form no part of the claimed design. The oblique shade lines in the drawings are used to show a reflective surface of a screen of the air purifier.