1. What Is Relative Humidity?

Relative humidity (RH) is the ratio of the partial pressure of water vapor to the equilibrium vapor pressure of water at a given temperature. It represents the amount of moisture in the air relative to the maximum amount the air can hold at that temperature.

2. How The Calculator Works

The calculator uses the relative humidity formula:

Where:

• \( e \) — Actual vapor pressure (Pa)
• \( e_s \) — Saturation vapor pressure (Pa)

Explanation: The formula calculates the percentage of moisture present in the air compared to the maximum moisture the air can hold at that temperature.

3. Importance Of Humidity Calculation

Details: Accurate humidity calculation is essential for weather forecasting, HVAC system design, agricultural planning, industrial processes, and maintaining comfortable indoor environments.

4. Using The Calculator

Tips: Enter both vapor pressure values in Pascals (Pa). Both values must be positive numbers for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between absolute and relative humidity?
A: Absolute humidity measures the actual amount of water vapor in the air (g/m³), while relative humidity expresses this as a percentage of the maximum possible at that temperature.

Q2: What are typical relative humidity ranges?
A: Comfortable indoor RH is typically 30-50%. Below 30% can cause dryness, above 60% can promote mold growth.

Q3: How does temperature affect relative humidity?
A: Warmer air can hold more moisture, so relative humidity decreases as temperature increases (if moisture content remains constant).

Q4: Why use Pascals as the unit for vapor pressure?
A: Pascals are the SI unit for pressure, providing standardization across scientific calculations. 1 kPa = 1000 Pa.

Q5: How is saturation vapor pressure determined?
A: Saturation vapor pressure depends primarily on temperature and can be calculated using various empirical formulas like the August-Roche-Magnus approximation.