We claim the ornamental design for the dryer exhaust duct alarm, as shown.
FIG. 1 is an isometric view of a top view showing our design.
FIG. 2 is an isometric view of the underside of our design
FIG. 3 is a right side elevation view.
FIG. 4 is a left side elevation view.
FIG. 5 is a rear end elevation view.
FIG. 6 is a side elevation view;
FIG. 7 is side elevation view; and,
FIG. 8 is an end view of our design.
The broken line showing of an electronic housing is included for the purpose of illustrating portions of the “article” and forms no part of the claimed design.