Many gas detectors can monitor Carbon Monoxide (CO), Nitrogen Dioxide (NO2), or Oxygen (O) in parking garages or other applications. Carbon Monoxide (CO) and Nitrogen Dioxide (NO2) are the harmful gases produced by cars and trucks. Oxygen deficiency ensures that occupants have enough breathable oxygen. Different transmitters might be needed for each gas as the concentration of the gases tends to gather at different heights in an area. Carbon Monoxide detectors are typically mounted at a height of 5 feet from the ground surface. Nitrogen Dioxide Monitors are typically mounted at a height of 2 feet from the ceiling. For more information, contact Jackson Systems at 888-652-9663 or find out more about wireless gas detectors at www.jacksonsystems.com.