Calculate CO concentration at high altitude

In summary, the conversation discusses converting 17,000ft to atm and calculating the equivalent CO concentration in mg/m^3 at that altitude. However, there is confusion over the units and calculations, with the initial conversion to atm being incorrect and subsequent calculations being affected by this error. The conversation also touches upon the use of the Ideal Gas Law and the importance of double checking calculations when they seem incorrect.
  • #1
jwingeart
2
0
Question:
You are cooking in a tent at 17,000ft with outside air temp at -15F. The concentration of CO in the tent is 40ppm. Calculate the equivalent CO concentration in mg/m^3.

First, I converted 17000ft to atm and got 501.5atm, which seems very wrong.

Next, I converted -15F to 247.039K.

I applied the Ideal Gas Law, PV=nRT

I tried to solve for V.

p=501.5 atm
n(molecular weight CO)=28
R (should be a constant)=.082056
T=247.039

I come up with a ridiculous answer. It seems simple, but I can't figure out where I'm going wrong.
 
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  • #2
Forgot to mention also, (but it's obvious) that the conditions are not at STP. (not 25C, not 1.0 atm)
 
  • #3
Show us how you calculated the pressure at that altitude?

Chet
 
  • #4
jwingeart said:
Question:
You are cooking in a tent at 17,000ft with outside air temp at -15F. The concentration of CO in the tent is 40ppm. Calculate the equivalent CO concentration in mg/m^3.

First, I converted 17000ft to atm and got 501.5atm, which seems very wrong.

Why do you think altitude is equivalent to atmospheres? Your calculation assumes that there is a water column 17000 feet tall somewhere.

Next, I converted -15F to 247.039K.

FWIW, this calculation is OK.

I applied the Ideal Gas Law, PV=nRT

I tried to solve for V.

p=501.5 atm
n(molecular weight CO)=28
R (should be a constant)=.082056
T=247.039

I come up with a ridiculous answer. It seems simple, but I can't figure out where I'm going wrong.

Well, for one thing thinking that the atmospheric pressure at 17000 feet altitude is 500 atmospheres. (Hint: the atmospheric pressure decreases with altitude, although not in a linear relationship.)
 
  • #5
jwingeart said:
First, I converted 17000ft to atm and got 501.5atm, which seems very wrong.

Check your units. At 17,000 ft, atmospheric pressure should be ~500 kPa, or 0.5 atm. If the answer you're getting is off by 3 orders of magnitude, this might be why.
 
  • #6
jwingeart said:
First, I converted 17000ft to atm and got 501.5atm, which seems very wrong.
So why didn't you stop right there?

It obviously is very wrong. When you get an answer that seems very wrong, you should stop and double check. Carrying a bad calculation forward is generally a very bad idea because that bad calculation oftentimes poisons all subsequent results.


SCP said:
Check your units. At 17,000 ft, atmospheric pressure should be ~500 kPa, or 0.5 atm.
That's wrong, too. One atmosphere is on the order of 100 kPa, so 500 kPa is about 5 atmospheres.
 
  • #7
D H said:
So why didn't you stop right there?

It obviously is very wrong. When you get an answer that seems very wrong, you should stop and double check. Carrying a bad calculation forward is generally a very bad idea because that bad calculation oftentimes poisons all subsequent results.



That's wrong, too. One atmosphere is on the order of 100 kPa, so 500 kPa is about 5 atmospheres.

It's that damn metric system confusin' everyone again.
 
  • #8
D H said:
SCP said:
Check your units. At 17,000 ft, atmospheric pressure should be ~500 kPa, or 0.5 atm. If the answer you're getting is off by 3 orders of magnitude, this might be why.
That's wrong, too. One atmosphere is on the order of 100 kPa, so 500 kPa is about 5 atmospheres.

Ah yes. I was thinking in millibars. Silly. In any case, at 17,000 ft you should get pressure at ~0.5 atm (or ~50 kPa).
 

Related to Calculate CO concentration at high altitude

1. How does altitude affect CO concentration?

As altitude increases, the concentration of carbon monoxide (CO) decreases. This is because at higher altitudes, the air is thinner and there is less oxygen available for combustion, resulting in less CO being produced. Additionally, winds and atmospheric mixing can also disperse CO more quickly at high altitudes, further reducing its concentration.

2. Why is it important to calculate CO concentration at high altitudes?

CO is a toxic gas that can have harmful effects on both humans and the environment. At high altitudes, where there is less oxygen and lower air pressure, CO can be even more dangerous as it can accumulate in the body faster and cause symptoms such as dizziness, nausea, and even death. Therefore, it is important to monitor and calculate CO concentration at high altitudes to ensure the safety of individuals and the environment.

3. What factors affect CO concentration at high altitudes?

Aside from altitude, other factors that can affect CO concentration at high altitudes include temperature, humidity, and wind speed. These factors can impact the rate of combustion and the dispersion of CO in the air. Additionally, human activities such as burning fossil fuels and wildfires can also contribute to elevated levels of CO at high altitudes.

4. How is CO concentration measured at high altitudes?

CO concentration at high altitudes can be measured using various instruments such as gas analyzers and air quality monitors. These devices can detect and measure the amount of CO in the air, usually in parts per million (ppm) or parts per billion (ppb). Additionally, researchers can also collect air samples and analyze them in a laboratory to determine the CO concentration.

5. What are the potential health effects of exposure to high CO concentration at high altitudes?

Exposure to high levels of CO at high altitudes can lead to various health effects, including headaches, dizziness, nausea, and shortness of breath. In severe cases, it can cause loss of consciousness and even death. Long-term exposure to high CO concentration can also have long-term health effects, such as heart disease and respiratory problems. Therefore, it is crucial to monitor and maintain safe levels of CO at high altitudes to protect human health.

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