why is the air at the top of a mountain hard to breathe?

Answer 1

Your lungs have to work harder to inhale the thinner air. As the air pressure decreases because of altitude, the air has less density, you must inhale more times to get the same volume of air as at sea level. Less air density also means less oxygen.

The answer is not simply "there is less oxygen", there is still the same percentage of oxygen, there is overall "less air" therefore less oxygen molecules to absorb with each breath.

Answer 2

The % of oxygen in the air becomes lower as elevation increases.

Elevation % of air
compared to sea level
Sea level 100%
5,000 feet (1524 m) 81%
10,000 feet (3048 m) 66%
15,000 feet (4572 m) 54%
17,000 feet (5182 m) (the highest pass the Caravan of Light will cross) 50%
29,035 feet (8850 m) (elevation of Mt. Everest) 30%

A simple but critically important fact about traveling to high altitude is that there is less air. If you have ever had anyone hold your head underwater in a swimming pool for longer than you wanted, you know how important air is. Air is made up of a number of gases including nitrogen, carbon dioxide, and oxygen. Your body needs oxygen to survive. Without proper precautions, at high elevation you can feel like you are breathing through a straw. You just don't get enough oxygen. The easiest place to breath is at sea level. That's where you have the most air. As you climb a mountain, the air gets thinner. The chart to the right will give you an idea of how the amount of air decreases as you go up.

Answer 3

The higher you go above sea level, the thinner the air gets- therefore, it gets harder to breathe. This is because air, believe it or not, has mass and weight- at sea level all the air above it is pressing down on it- as you go higher up, there's just less air pressing down since you've passed above some of it. So, the higher you get above sea level, the less air you breathe in with each breath, whether you're on a mountain or in a plane, or whatever. In fact, this is why all pilots MUST wear an oxygen mask if the're going to be above 10,000 feet for more than a half hour- the air at that altitude is so thin you'll slowly lose conciousness and not even be aware of it (this is called hypoxia, by way: oxygen starvation).
So, in a nutshell: air is harder to breathe up high because the pressure is lower (or, the air is thinner- means the same thing). The densest air is at sea level, and gets lower the higher up you go since there's less air above it pushing down on it.

Answer 4

The air at the top of a mountain is not hard to breathe. It's hard to breathe at the top of a mountain because there is less oxygen in the atmosphere at higher elevations. Your body still breathes the same way, but it doesn't get the same amount of oxygen each time, making it seem difficult to breathe.

Answer 5

Pressure is the weight of air above you. As you ascend, you rise above more and more of the air. The pressure decreases. Since the ratio of oxygen in the air doesn't change until you get above 100 km or so, the pressure exerted by the oxygen decreases. This does the following:

1) You have to breathe more rapidly to get the same amount of oxygen in the same amount of time. Since the muscles that move the lungs use oxygen, this means that the lungs use a higher proportion of the total oxygen breathed in at higher altitudes, leaving less for the other parts of the body.

2) The lower pressure of oxygen means that oxygen diffuses less slowly through the lung tissue into the blood. Since the blood still circulates through the lungs at roughly the same speed, this means that the blood doesn't have enough time to absorb all the oxygen it can. Thus, the blood leaving the lungs is partially oxygen-starved at high altitudes.

3) The lower pressure of oxygen also causes the hemoglobin of the blood to have a lower affinity for oxygen. This means that less tends to be absorbed into the blood. Also, less oxygen dissolves in the liquid blood plasma, so there is less "spare" oxygen in that as well.

All these reasons mean that it is much harder to breathe at high altitudes.

Answer 6

The oxygen in your blood is under pressure. In order for oxygen to move from the air you breathe into your blood, it must have enough pressure to cross the barrier in your lungs to get into your blood. At higher altitudes, there is just as much oxygen in the air, but it is at a lower pressure. The higher you go, the lower the pressure. Eventually, you'll get high enough and the pressure low enough that no matter how hard you breathe, no oxygen will cross into your blood.

Answer 7

The higher your altitude, the thinner the atmosphere, therefore, the less oxygen you're breathing. It takes a greater volume of air in your lungs (& more breaths) to get the same amount of oxygen you would at sea level, for example.

Answer 8

The higher the altitude the thinner the air. Meaning there is less oxygen in the air, at a greater height

Answer 9

The higher the attitude the higher the density,and higher the density the lower amount of air left.That means it takes the human body to breathe more times than usual because the low amount of oxygen.

Answer 10

The higher the altitude, the thinner the air gets.
.:., there is less of oxygen present causing it hard to breathe.