Which of the following environmental factors do NOT increase the probability that M tuberculosis will be transmitted?

  •  Negative pressure in an infectious TB patient’s room.
  •  Inadequate local or general ventilation that results in insufficient dilution or removal of infectious droplet nuclei.
  •  Improper specimen handling procedures that generate infectious droplet nuclei.
  •  Exposure in small enclosed spaces.
  •   Recirculation of air containing infectious droplet nuclei.