1. What is Relative Humidity?

Relative Humidity (RH) is a measure of the amount of water vapor present in air compared to the maximum amount the air can hold at that temperature. It's expressed as a percentage and is a key parameter in meteorology, HVAC systems, and industrial processes.

2. How Does the Calculator Work?

The calculator uses the Relative Humidity equation:

Where:

• \( RH \) — Relative Humidity (%)
• \( P_v \) — Vapor pressure (Pa)
• \( P_{sat} \) — Saturation pressure (Pa)

Explanation: The equation calculates what percentage the actual vapor pressure is of the saturation vapor pressure at the same temperature.

3. Importance of Relative Humidity

Details: RH affects human comfort, building design, industrial processes, and weather forecasting. Proper humidity levels are crucial for health, material preservation, and many manufacturing processes.

4. Using the Calculator

Tips: Enter both vapor pressure and saturation pressure in Pascals (Pa). Both values must be positive numbers. The saturation pressure can be found from temperature using the Clausius-Clapeyron equation or standard tables.

5. Frequently Asked Questions (FAQ)

Q1: What is a comfortable RH range for humans?
A: Typically 30-60%. Below 30% can cause dry skin and respiratory irritation, while above 60% promotes mold growth.

Q2: How does temperature affect RH?
A: Warmer air can hold more water vapor, so RH decreases as temperature increases if the absolute moisture content stays the same.

Q3: What instruments measure RH?
A: Hygrometers, psychrometers, and modern electronic sensors can measure relative humidity directly.

Q4: Why is RH important in industrial processes?
A: Many manufacturing processes (paper, textiles, food) require specific humidity levels for quality control and process efficiency.

Q5: What's the difference between RH and absolute humidity?
A: RH is relative to temperature, while absolute humidity measures the actual mass of water vapor per volume of air, regardless of temperature.