TV report was going on about how Oxygen levels were sometimes below required levels, and would be below that allowed in an office on the ground!! What drivvle. Since when can you compare an office on the ground with an aircraft, and since when did any employer have control over O2 levels in his office - usually depends on its elevation!
Also, aircraft O2 levels are controlled by the pressurisation system which controls to a differential pressure (up to 7.9 psi) on the 737, resulting in cabin altitudes up to 8000 feet. The cabin altitude is never allowed to exceed this.