A smoke detector according to various embodiments discussed herein can use a non-radioactive ionization technique to detect the presence of smoke and/or other particulate matter. A non-radioactive ionizing detector may use a LED such as an ultraviolet light emitting diod in combination with a pair of conductive plates, one of which is coated with a photocatalyst coating. When the light strikes the photocatalyst coating, ions can be generated that change a charge characteristic of the photocatalytic coated plate. The occurrence of an alarm can be detected based on a measured charge magnitude existing between the two plates.