At what altitude will altitude sickness occur? Why is there less oxygen at higher altitudes?

The Qinghai-Tibet Railway is the highest and longest plateau railway in the world. It is also one of the four major projects in China in the new century. It is the first railway leading to the hinterland of Tibet, referred to as the Qinghai-Tibet Line. Tibet is also a place that many friends yearn for. Just thinking about it makes them feel particularly beautiful. If you are interested, let's learn about it in advance!

Contents of this article

1. At what altitude will altitude sickness occur?

2. Why is there less oxygen at higher altitudes?

3. The world's highest altitude and longest plateau railway

At what altitude will altitude sickness occur?

The altitude at which altitude sickness occurs is also related to the individual's physical condition. Generally speaking, when people from the plains quickly enter a plateau above 3,000 meters above sea level, 50% to 75% of them will experience altitude sickness.

The incidence of this disease is lower in the elderly than in the young, and lower in women than in men. The incidence of altitude sickness is positively correlated with the body mass index of men, but not with the body mass index of women, indicating that obese men are more likely to suffer from altitude sickness.

Why is there less oxygen at higher altitudes?

Take the Qinghai-Tibet Plateau as an example. It is very simple to say that due to the high altitude of the Qinghai-Tibet Plateau, the mass of the atmosphere is mainly in the troposphere, and the thickness of the troposphere varies with latitude. The low latitude is 17 to 18 kilometers, the mid-latitude is 10 to 12 kilometers, and the high latitude is 8 to 9 kilometers.

The Qinghai-Tibet Plateau is too high, with an average altitude of more than 4,500 meters. The air above it has basically reached the stratosphere, where the air pressure is low and the air is thinner. The stratosphere has less oxygen content and there is ozone at the top, which affects people's normal breathing.

Therefore, generally speaking, the higher the altitude on the plateau, the thinner the air.

The world's highest and longest plateau railway

The Qinghai-Tibet Railway is the highest and longest plateau railway in the world. It is also one of the four major projects in China in the new century. It is the first railway to the hinterland of Tibet, referred to as the Qinghai-Tibet Line. It is a Class I national railway connecting Xining City, Qinghai Province to Lhasa City, Tibet Autonomous Region.

About 85% of the Qinghai-Tibet Railway is located above 4,000 meters above sea level, with an average annual temperature below 0°C. The oxygen content in the air in most areas is only about 50%-60% of that in the inland areas.

The Qinghai-Tibet Railway is known as a "forbidden zone" where human beings cannot survive due to its high altitude, lack of oxygen, rampant sandstorms, strong ultraviolet rays, and many natural sources of disease.

The ecological environment of the Qinghai-Tibet Railway is sensitive and fragile. In order to improve the ecological environment along the line, the railway achieved "zero pollution discharge" on the ground and on trains and became China's first "environmentally friendly railway".