How much air is at 46000 feet?

At 46,000 feet, the air pressure is significantly lower than at sea level, approximately 21% of the pressure at sea level. Consequently, the density of air is also much lower, making it difficult for humans to breathe without supplemental oxygen. This altitude is typically above the cruising altitude of commercial flights, where the air is thin and oxygen levels are reduced. In general, at this height, the air is about 1/4 as dense as it is at sea level.