Air Density Calculator

The air density calculator measures how the air molecules are packed in air. You can estimate the ρ (air density) based on the temperature and the pressure.

Let’s have a look at the variables of the density of air and how these variables affect the air density.

Density of Air at Sea Level?

At sea level, the atmospheric pressure is maximized due to high air pressure. Hence the air is denser at sea level and we can figure this out by the air density calculator. 

The density of the air is denoted by the Greek letter Rho (ρ) and it is the measure of the mass per unit volume and we represent the density of air in kg/m3 or g/m3. Moreover, we have also designed another density calculator that helps you to calculate density of air in kg m3.

Dry air mostly consists of Nitrogen (~78 %) Oxygen (~21 %), the remaining 1 % contain other gasses like Argon, Carbon Dioxide, Neon, Helium etc. The partial pressure or  density of air at sea level can only be measured by finding the individual pressure of various gases.The partial pressure calculator enables us to measure the partial pressure of various gas to find the  density of air at sea level. The air density normally changes; there can be minor changes in the density of various gasses.

Density of Air Equation:

We are taking the temperature in Kelvin and it represents the absolute temperature. 

There is the specific gas constant for the dry air,which is equal to 287.058 J/(kg·K).

The other specific gas constant for water vapor equal to 461.495 J/(kg·K). The density of air calculator utilizes the specific gas constant and water to estimate the air density.

How to calculate air density of air by the following formula?

ρ = [(Pd / (Rd * T)) + (Pv / (Rv * T))]

where:

Pd = Pressure of dry air

Pv = Water vapor pressure 

T = Temperature in Kelvins

Rd = Specific gas constant for dry air [287.058 J/(kg·K)]

Rv = Specific gas constant for water [461.495 J/(kg·K)]

We can use the ideal Gas Law calculator to find the relative pressure and temperature in Kelvin.

How to Calculate Air Density?

For measuring the air density at a given location, you need some basic weather parameters like the pressure and temperature. To calculate air density from pressure and temperature, you need to understand some basic units of pressure and temperature.

Air Pressure:

The air pressure is a  force exerted on a surface by the air above it as gravity pulls it to Earth. The air pressure is commonly measured with a barometer or in Pascals.

The standard SI unit of pressure is Pascal and the other units are expressed as follows:

• Pascals (Pa) 
• Standard Atmospheres (ATM)

• Tor (Torr)

• bar (bar)

• Pounds per Square Inch (psi or lb/in2)

• Technical Atmosphere (at or kgf/cm2)

• Barad (Ba)

• Pièze (ps)

Air Temperature:

The basic units of temperature are Kelvin (K), centigrade or Celsius (C), and Fahrenheit (F).  You need to convert the Fahrenheit to Celsius and Kelvin to calculate air density. 

Dew Point:

The dew point is the temperature at which the water vapor starts to condense and Dew point is the temperature below which the water vapor starts to condense, in °C.

Our air density calculator is able to use one of these values to compute the other, or you can also use our dew point calculator.

Density of Air Lb/Ft3 of Pressure:

The density of the air at constant pressure, say 1pascel is different at various temperatures. When we calculate air density at various temperatures, we find various values.

 The given table below represents the following reading. The air density calculator makes it possible to find the density of the dry air.

Density of air	Pressure	Density of air lb/ft3
density of air at 15 c	1 Pascale	0.00000075474
density of air at 20c	1 Pascale	0.00000074187
density of air at 22 c	1 Pascale	0.00000073684
density of air at 25 c	1 Pascale	0.00000072943
density of air at 40 c	1 Pascale	0.00000069449

We can calculate the air-density in various units like [lbm/ft3], [sl/ft3*10-3] , [lbm/gal(US liq)], [kg/m3]. How to calculate density of air in the above mentioned units, and their connection with the specific weight and thermal expansion. 

In the table below we have distinguished the specific weight and thermal expansion coefficient at the various temperatures.

Temperature	Density				Specific weight		Thermal expansion coefficient
[°F]	[lbm/ft3]	[sl/ft3*10-3]	[lbm/gal(US liq)]	[kg/m3]	[lbf/ft3]	[N/m3]	[x10-3 °F-1]
-100	0.1104	3.431	0.01476	1.768	0.1104	17.34	2.83
-50	0.0968	3.010	0.01295	1.551	0.0968	15.21	2.48
-20	0.0902	2.803	0.01206	1.445	0.0902	14.17	2.30
0	0.0862	2.681	0.01153	1.382	0.0862	13.55	2.20
10	0.0844	2.624	0.01128	1.352	0.0844	13.26	2.15
20	0.0826	2.569	0.01105	1.324	0.0826	12.98	2.10
30	0.0810	2.516	0.01082	1.297	0.0810	12.72	2.06
40	0.0793	2.466	0.01061	1.271	0.0793	12.46	2.02
50	0.0778	2.418	0.01040	1.246	0.0778	12.22	1.98
60	0.0763	2.372	0.01020	1.222	0.0763	11.99	1.94
70	0.0749	2.327	0.01001	1.199	0.0749	11.76	1.90
80	0.0735	2.284	0.00982	1.177	0.0735	11.55	1.87
100	0.0709	2.203	0.00948	1.135	0.0709	11.14	1.80
120	0.0685	2.128	0.00915	1.097	0.0685	10.75	1.74
140	0.0662	2.057	0.00885	1.060	0.0662	10.40	1.68
160	0.0641	1.991	0.00856	1.026	0.0641	10.06	1.63
180	0.0621	1.929	0.00830	0.994	0.0621	9.75	1.58
200	0.0602	1.870	0.00804	0.964	0.060	9.45	1.53
250	0.0559	1.738	0.00747	0.896	0.0559	8.78	1.41
300	0.0522	1.622	0.00698	0.836	0.0522	8.20	1.30
350	0.0489	1.521	0.00654	0.784	0.0489	7.69	1.23
400	0.0461	1.432	0.00616	0.738	0.0461	7.24	1.16
450	0.0436	1.354	0.00582	0.698	0.0436	6.84	1.10
500	0.0410	1.274	0.00548	0.656	0.0410	6.43	1.05
600	0.0371	1.152	0.00496	0.599	0.0371	5.82	0.96
700	0.0340	1.057	0.00455	0.545	0.0340	5.35	0.88
800	0.0315	0.978	0.00421	0.5042	0.0315	4.94	0.81
1000	0.0272	0.845	0.00363	0.4354	0.0272	4.27	0.70
1200	0.0239	0.743	0.00319	0.3827	0.0239	3.75	0.61
1400	0.0213	0.663	0.00285	0.3416	0.0213	3.35	0.54
1600	0.0193	0.599	0.00257	0.3085	0.0193	3.03	0.49
1800	0.0176	0.546	0.00235	0.2813	0.0176	2.76	0.45
2000	0.0161	0.501	0.00216	0.2583	0.0161	2.53	0.42

Working of Air Density Calculator:

• Working of Air Density calculator:The air density from pressure and temperature can be measured  by the following instructions:Input:
  • Enter the air pressure
  • Select the air temperature
  • Choose the Air type
  • Relative humidity of air
  • Hit the calculate button to find the  air density

  Output:

  The air density calculator estimates the following calculations:

  • Dew point of air
  • Pressure of the dry air 
  • Water vapor pressure
  • Air density of air

FAQs:

What is Standard Air Density?

The value of the air density is 1.29 grams/liter or 0.07967 pounds/cubic foot at the 0 degree and 32 degree Fahrenheit at the average sea level. The barometric pressure is 29.92 inches of Hg or 760 mm Hg.

What is the Density of Air at 25 Celsius?

The density of air in kg m3 is 1.168 kg/m3 at (25 °C and 100 kPa). The air density calculator can find the density of air for both dry and moist atmospheres.

Is air Pressure a Density of Air?

The air pressure is a factor of the density of air and the air density is mass per unit volume. The air pressure reduces the altitude and air density at altitude calculator is a better option to find the air density.

Does Humidity Increase Air Density?

The temperature, air pressure and the humidity have a small effect on the air’s density. Dry air is lighter than the moist air, and it is the main reason the dry air goes upward as compared to the moist air. The air density calculator makes it possible to find the humidity level at a certain atmosphere.

Why does Air Density Decrease with Humidity?

Water vapors  are relatively lighter as compared to diatomic oxygen and Nitrogen. When the vapor content increases in the moist air, then the ratio of the Nitrogen and Oxygen decreases in per unit volume. The density of air at STP is 1.2754 kg / m³ an it is going to decrease 

Conclusion:

The air density calculator measures the air density of dry and moist air by the atmospheric pressure, temperature, and relative humidity. When we are able to predict the following variable, it is easy to forecast the weather forecast.

References:

From the source of wikipedia: Density of air, Temperature

From the source of iflycoast.com: Understanding Air Density, Effects of lower density on humans