Relative Humidity To Water Vapor Pressure Calculator

Water Vapor Pressure Equation:

\[ e = \frac{RH}{100} \times e_s \]

Water Vapor Pressure (e):

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1. What is Water Vapor Pressure?

Water vapor pressure is the partial pressure of water vapor in any gas mixture. It represents the contribution of water vapor to the total pressure and is a key parameter in atmospheric science, meteorology, and various engineering applications.

2. How Does the Calculator Work?

The calculator uses the water vapor pressure equation:

\[ e = \frac{RH}{100} \times e_s \]

Where:

\( e \) — Water vapor pressure (hPa)
\( RH \) — Relative humidity (%)
\( e_s \) — Saturation vapor pressure (hPa)

Explanation: This equation calculates the actual vapor pressure from relative humidity and the saturation vapor pressure at the same temperature.

3. Importance of Water Vapor Pressure Calculation

Details: Water vapor pressure is essential for understanding humidity levels, predicting weather patterns, calculating dew point, and designing HVAC systems. It's also crucial in industrial processes where moisture control is important.

4. Using the Calculator

Tips: Enter relative humidity as a percentage (0-100%) and saturation vapor pressure in hPa. The saturation vapor pressure depends on temperature and can be calculated using various formulas like the August-Roche-Magnus approximation.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between absolute and relative humidity?
A: Absolute humidity is the actual amount of water vapor in the air, while relative humidity is the ratio of the current vapor pressure to the saturation vapor pressure at the same temperature.

Q2: How does temperature affect vapor pressure?
A: Saturation vapor pressure increases exponentially with temperature, meaning warm air can hold much more water vapor than cold air.

Q3: What are typical values for water vapor pressure?
A: At room temperature (20°C), saturation vapor pressure is about 23.4 hPa. Actual vapor pressure varies with humidity but is typically between 5-20 hPa in most environments.

Q4: How is this related to dew point?
A: Dew point is the temperature to which air must be cooled to become saturated with water vapor. It's directly related to vapor pressure - higher vapor pressure means higher dew point.

Q5: Why use hPa as the unit?
A: Hectopascals (hPa) are equivalent to millibars (mb) and are the standard unit for atmospheric pressure measurements in meteorology. 1 hPa = 100 Pa = 1 mb.