Boiling point - Wikipedia
Amount of air that can be dissolved in water - decreases with temperature and increases with pressure. Air temperature changes the air pressure. For example, as the air warms up on a hot summer day, the molecules in the air become more active and they use up. It is shown that the maximum rate of change of water-table height with air pres- temperature and pressure, C is of the Gas equation ]or entrapped air.Lesson 5.2.2 - Temperature, Air Pressure, and Humidity
When contents are removed from the can, then the mass of the contents will be reduced in the can. Because there is less mass in the can with a constant volume, the pressure will decrease. This pressure decrease in the can results in a temperature decrease.
The contents coming out of the can also cool in temperature but for another reason. Outside of the can the volume is not held constant. Thus the contents are free to expand when they move from the high pressure in the can to the low pressure outside of the can.
Expansional cooling causes the contents coming out of the can to cool. This effect can be noticed in spray-on deodorants.
In the second example, a compressor is shown. This is used in appliances such as refrigerators. The refrigerant air is pressurized into the compressor meaning the pressure increases as more air is squeezed into the same volume.
What Happens to Air Pressure With an Increase in Water Vapor? | Sciencing
This causes a temperature increase. Shifting Gases The amount of air composed of water vapor is typically 1 to 4 percent. All gases in the air, including water vapor, exist in constantly shifting proportions.
Since their total must equal percent, an increase or decrease in the percentage occupied by water vapor results in a decrease or increase of the percentages of other gases.
Since atmospheric pressure at sea level is always approximately 1 bar, an increase in water vapor at any given location changes it very little.
thermodynamics - Water pressure vs temperature - Physics Stack Exchange
At high altitudes overall atmospheric pressure is lower and increases in water vapor have a greater -- though still relatively small -- impact. Changing Saturation However, there's another "air pressure" measurement that does change significantly with increasing water vapor. This is the saturated vapor pressure, or the proportion of atmospheric pressure attributable to the water vapor itself.
The amount of water vapor in the air, or humidity, depends on evaporation.
Evaporation depends on water temperature -- as water warms, more molecules evaporate from its surface. Water in cooler air evaporates less and water in warmer air evaporates more and faster -- hence the relationship between heat and humidity.