1. What is Air Density?

Definition: Air density (ρ) is the mass per unit volume of Earth's atmosphere, typically measured in kg/m³.

Standard Value: At Standard Temperature and Pressure (STP: 101325 Pa, 273.15 K), dry air has a density of approximately 1.225 kg/m³.

2. How Does the Calculator Work?

The calculator uses the ideal gas law formula:

Where:

• ρ — Air density (kg/m³)
• P — Absolute pressure (Pascals)
• R_specific — Specific gas constant for dry air (287.058 J/(kg·K))
• T — Absolute temperature (Kelvin)

Explanation: Air density decreases with increasing temperature and decreasing pressure.

3. Importance of Air Density

Applications: Critical for aerodynamics, HVAC design, meteorology, and various engineering calculations involving air flow.

4. Using the Calculator

Tips:

• For standard conditions, use defaults (101325 Pa, 273.15 K)
• For room temperature (20°C), use 293.15 K
• For sea level pressure, use 101325 Pa

5. Frequently Asked Questions (FAQ)

Q1: What's the specific gas constant value for air?
A: The specific gas constant for dry air is 287.058 J/(kg·K).

Q2: How does altitude affect air density?
A: Air density decreases with altitude due to decreasing pressure, despite lower temperatures.

Q3: What's the difference between density and specific weight?
A: Density is mass per volume (kg/m³), while specific weight is force per volume (N/m³), related by gravity.

Q4: How does humidity affect air density?
A: Humid air is less dense than dry air at the same temperature and pressure because water vapor is lighter than dry air.

Q5: What are typical air density values at different altitudes?
A: Sea level: ~1.225 kg/m³, 1500m: ~1.056 kg/m³, 3000m: ~0.909 kg/m³, 5000m: ~0.736 kg/m³.