The concentration of oxygen on Kilimanjaro is lower than at sea level due to the high altitude. The summit of Kilimanjaro, Uhuru Peak, is located at an elevation of 5,895 meters (19,341 feet), which means that the air pressure and oxygen levels are significantly lower than at sea level.

At the summit, the oxygen concentration is about 50% of what it is at sea level. This reduction in oxygen levels can make breathing more difficult and can lead to symptoms of altitude sickness such as headaches, fatigue, and shortness of breath.

To mitigate the effects of altitude sickness, climbers should take their time ascending the mountain and allow their bodies to acclimatize to the high altitude. This involves taking frequent breaks, drinking plenty of water, and following a slow and steady pace. In some cases, climbers may also need to use supplemental oxygen to help alleviate the symptoms of altitude sickness.