An apparatus including a band； and a first device configured to attach to a person's wrist using the band； wherein the first device includes a first carbon monoxide level detector； wherein the first device includes a housing and a second device configured to be moved with respect to the housing from a first state to a second state； wherein in the first state a person cannot blow into the second device and cause a carbon monoxide level of the person's breath to be detected by the first carbon monoxide level detector； and wherein in the second state the person can blow into the second device and cause a carbon monoxide level of the person's breath to be detected by the first carbon monoxide level detector. The first device may include a second carbon monoxide level detector which is configured to detect a carbon monoxide level in ambient air.
