1. What is Absolute Humidity?

Absolute humidity is the measure of water vapor (moisture) in the air, regardless of temperature. It's expressed as grams of water vapor per cubic meter of air (g/m³).

2. How Does the Calculator Work?

The calculator uses the absolute humidity equation:

Where:

• \( AH \) — Absolute humidity (g/m³)
• \( RH \) — Relative humidity (decimal, 0-1)
• \( e_s \) — Saturation vapor pressure (kPa)
• \( R \) — Gas constant (8.314 J/(mol·K))
• \( T \) — Temperature (K)
• 18.015 — Molecular weight of water (g/mol)

Explanation: The equation converts relative humidity to absolute humidity by accounting for the maximum possible water vapor (saturation vapor pressure) at the given temperature.

3. Importance of Absolute Humidity

Details: Absolute humidity is important in meteorology, HVAC design, industrial processes, and health applications as it directly measures the actual water vapor content in air.

4. Using the Calculator

Tips: Enter relative humidity as a decimal (0-1), saturation vapor pressure in kPa, and temperature in Kelvin. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: How does absolute humidity differ from 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: What are typical absolute humidity values?
A: Values range from near 0 in cold/dry air to about 30 g/m³ in very hot/humid conditions. Comfortable indoor levels are typically 5-15 g/m³.

Q3: How do I get saturation vapor pressure?
A: It can be calculated from temperature using the Magnus formula or obtained from thermodynamic tables.

Q4: Why use Kelvin for temperature?
A: Kelvin is an absolute temperature scale required for gas law calculations. To convert from Celsius: K = °C + 273.15.

Q5: What are applications of absolute humidity?
A: Used in meteorology, HVAC design, drying processes, pharmaceutical manufacturing, and climate control systems.