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17 votes
Accepted

Where do bad smells eventually go?

If you are smelling something, you are inhaling gases, particles, or a combination of the two. They don't normally build up in the atmosphere because of three reasons: transport/dilution (which you ...
  • 12.7k
13 votes

Why does warm air "hold" more moisture?

Saying that warm air "holds" more moisture is technically incorrect, but is a common colloquialism. Let's break it down to the technicalities. Let's consider a glass of water with a vacuum (no air) ...
13 votes
Accepted

Is volume of air increasing as CO2 levels increase?

[Major edits below] In short the answer is NO. Before we get into volume changes, I have to say that volume is a tricky measure to apply to the atmosphere as a whole, because there is no clear limit ...
  • 17.1k
8 votes

Why is the Earth's shadow blue?

To my eyes, the belt of Venus looks purple, which didn't makes sense to me, as the very short wavelength of purple light should have been scattered long before arriving back there. Then all made sense ...
  • 20.7k
8 votes
Accepted

Why air do not suffer density stratification of its gaseous components?

So, naively, one would expect the heavier gasses to pool in the lower atmosphere and the light ones at the top. That's overly naive. That same naive expectation would lead one to think that uranium ...
  • 20.7k
7 votes
Accepted

Why is the Earth's shadow blue?

How can the air in the Earth's shadow scatter blue light if it doesn't get any direct illumination, and any indirect illumination getting back there should be VERY depleted in blue (i.e. mostly red ...
  • 421
7 votes

If a specific mass of air is polluted, will the pollution stick with it?

Air is a fluid, as such it tends to mix and concentrations, of anything, tend to disperse into the wider volume. Erik's cup of tea metaphor is pretty accurate, currents of air will pull apart your ...
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6 votes
Accepted

Do perfumes and deodorants contribute to global warming?

Maybe a little, but not much. Personal care products that have a strong odor are typically associated with volatile organic compound (VOC) emissions. VOCs are not really greenhouse gases, because ...
  • 12.7k
6 votes

Why does warm air "hold" more moisture?

The water molecule is just another molecule in the atmosphere - except that it's triatomic, whereas 99.97% of the dry atmosphere is monatomic (Argon) and diatomic (Oxygen and Nitrogen). It's also ...
  • 131
6 votes

Why does warm air "hold" more moisture?

What is the deep physics or chemistry reason this happens? In one word, entropy. In a thousand words (i.e., a picture), Source: Wikipedia article on Phase Diagram The above is a phase diagram of ...
  • 20.7k
6 votes

Why air do not suffer density stratification of its gaseous components?

But despite of that, there is no reports of miners dying because on the top of the cavity the air was only nitrogen or oxygen at the bottom. Yes and no, miners die from other causes, like lack of ...
5 votes
Accepted

If a specific mass of air is polluted, will the pollution stick with it?

Like many of my answers on this Stack Exchange, the answer is yes and no. Part of it depends on the pollutant itself. Let's call the mass by it's technical term, a parcel. There are a couple things ...
5 votes

Is volume of air increasing as CO2 levels increase?

Let me answer this question indirectly. When a pressure cooker partially filled with liquid water is heated up, there will be more water vapour molecules in the air inside pressure cooker but volume ...
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4 votes

When it is said that air moves from warm object to a cold object, how is it possible that air moves from high pressure area to low pressure area?

You are correct that air generally moves along the surface from high pressure towards low pressure (not directly, but deflected due to the coriolis effect). However, this does not imply that it is ...
  • 101
4 votes

Do sound waves from volcanic eruptions travel around the world?

Yes, if you include low frequency pressure changes as would be recorded on a barometer as sound waves. The 2022 Hunga Tonga eruption sent atmospheric pressure waves that were detected multiple times ...
4 votes

What is the current atmospheric concentration of $\small\sf{CO_2}$ in the atmosphere in atm (or bar)?

What I think you are asking for is the partial pressure of carbon dioxide in the atmosphere. The partial pressure of carbon dioxide can be determined, where, $P_{CO_2} \ = \ x_{CO_2}\cdot P_{atm}$ One ...
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3 votes

What is the current atmospheric concentration of $\small\sf{CO_2}$ in the atmosphere in atm (or bar)?

Not nearly so elegant as @fred answer: 400 ppm = 0.04% , then CO 2 is 0,04 % or 0.0004 atm.
  • 1,013
3 votes

What would happen to the earth if we removed nearly all of the air?

We already have a model of an atmosphere-stripped Earth at hand, it's called Mars. Essentially, the loss of air on Mars meant more things didn't happen any longer than did happen. Erosion and ...
  • 2,676
3 votes

How do meteorologists accurately measure outdoor air temperature? There's sunlight, local trapping of air, radiant heat, precipitation

True air temperature may be an elusive quantity to measure but shielding thermometers and sensors from direct solar radiation has been the main approach for a long time. The best results are provided ...
2 votes
Accepted

What is the relationship between air pressure and temperature?

Or if the math of the other answers is a bit complex, in a broad sense, the balancing relationship is: $$\frac{\mathrm{density} \cdot \mathrm{temperature}}{\mathrm{pressure}} = \mathrm{constant}$$ For ...
1 vote
Accepted

What was the oxygen concentration in the air during the late miocene period?

R. Tappert et al (2013) used carbon isotopes in ambers as proxies for atmospheric oxygen concentrations. Their work indicates an initial Miocene O2 concentration of 16% and rising to about 20% at the ...
1 vote

Does Start / Stop technology in cars have an impact on air quality?

From Wikipedia: In automobiles, a start-stop system or stop-start system automatically shuts down and restarts the internal combustion engine to reduce the amount of time the engine spends idling, ...
  • 2,636
1 vote

Does Start / Stop technology in cars have an impact on air quality?

Generally idling will cause pollution in specific isolated areas and start stop technology could irradicate that pollution. Here I will concentrate not on the global impact of the pollutants but at ...
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