1. What is Absolute Humidity?

Absolute Humidity (AH) measures the actual amount of water vapor in the air, expressed as grams of water vapor per kilogram of dry air (g/kg). Unlike relative humidity, it doesn't depend on temperature.

2. How Does the Calculator Work?

The calculator uses the absolute humidity equation:

Where:

• \( AH \) — Absolute humidity (g/kg)
• \( RH \) — Relative humidity (%)
• \( P_{sat} \) — Saturation vapor pressure (Pa)
• \( R_v \) — Specific gas constant for water vapor (461.5 J/kg·K)
• \( T \) — Temperature (K)

Explanation: The equation converts relative humidity to absolute humidity using the relationship between water vapor pressure and temperature.

3. Importance of Absolute Humidity

Details: Absolute humidity is crucial for meteorological studies, HVAC system design, industrial processes, and understanding human comfort levels.

4. Using the Calculator

Tips: Enter relative humidity as percentage, saturation vapor pressure in Pascals, and temperature in Kelvin. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between absolute and relative humidity?
A: Absolute humidity measures actual water vapor content, while relative humidity measures how close the air is to saturation at its current temperature.

Q2: How do I find saturation vapor pressure?
A: Saturation vapor pressure can be calculated using the Antoine equation or looked up in thermodynamic tables based on temperature.

Q3: What are typical absolute humidity values?
A: Near sea level, absolute humidity typically ranges from 0 g/kg in dry deserts to about 30 g/kg in very humid tropical conditions.

Q4: Why use Kelvin for temperature?
A: Kelvin is used because it's the absolute temperature scale required by the gas law in the equation.

Q5: Can I use this for any altitude?
A: The calculation is valid for any altitude, but saturation vapor pressure decreases with altitude due to lower atmospheric pressure.