AIR ALERT - STUDY SAYS HALF OF ALL PASSENGERS SUFFER OXYGEN DEPRIVATION! A team of Belfast researchers measuring oxygen saturation levels - the amount of oxygen carried in the blood, found that before take off for both short and long haul flights, saturation levels averaged 97% but for 54% of travellers these fell on average to 93% or less at altitude - a level at which respiratory specialists would prescribe extra oxygen!AIR ALERT - STUDY SAYS HALF OF ALL PASSENGERS SUFFER OXYGEN DEPRIVATION! A team of Belfast researchers measuring oxygen saturation levels - the amount of oxygen carried in the blood, found that before take off for both short and long haul flights, saturation levels averaged 97% but for 54% of travellers these fell on average to 93% or less at altitude - a level at which respiratory specialists would prescribe extra oxygen!