1. What is Relative Humidity?

Relative Humidity (RH) is the ratio of the current amount of water vapor in the air to the maximum amount the air can hold at that temperature, expressed as a percentage. It indicates how close the air is to saturation.

2. How Does the Calculator Work?

The calculator uses the Relative Humidity formula:

Where:

• \( RH \) — Relative Humidity (%)
• \( SH \) — Specific Humidity (kg/kg)
• \( SH_{sat} \) — Saturation Specific Humidity (kg/kg)

Explanation: The formula calculates the percentage of moisture in the air relative to the maximum moisture capacity at the same temperature.

3. Importance of Relative Humidity Calculation

Details: Relative humidity is crucial for weather forecasting, climate studies, agricultural planning, industrial processes, and maintaining comfortable indoor environments. It affects human comfort, health, and various material properties.

4. Using the Calculator

Tips: Enter specific humidity and saturation specific humidity values in kg/kg. Both values must be positive, and SH should not exceed SH_sat for valid results.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between specific and relative humidity?
A: Specific humidity measures the actual mass of water vapor per mass of air, 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 and feel uncomfortable.

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

Q4: Why can't specific humidity exceed saturation specific humidity?
A: Saturation specific humidity represents the maximum water vapor air can hold at a given temperature. Exceeding this would result in condensation.

Q5: How is relative humidity measured in practice?
A: Typically using hygrometers, psychrometers, or electronic sensors that measure various properties affected by moisture content.