OBSERVATIONS made by Pugh on Mount Everest in 1953 showed that the relationship between barometric pressure and altitude corresponded more closely with that of Zuntz, Loewy, Müller and Caspari1 ...

Atmospheric pressure at sea level is about 101,000 Pa (101 kPa) but just 27,000 Pa (27 kPa) at the cruising altitude of a passenger plane.

Atmospheric pressure decreases exponentially with altitude, causing a drop in blood oxygen saturation level to around 90% (73 hPa) in healthy passengers at cruising altitude, explain the researchers.

Bosch Sensortec has launched a barometric pressure sensor for smartphones, wearable and hearable devices. The BMP390 delivers altitude tracking in smartphones as well as wearable and hearable devices.