It tells us how much does a certain volume of air weigh. The basic definition of air density is very similar to the general definition of density. Rv is the specific gas constant for water vapor equal to 461.495 J/(kg.Rd is the specific gas constant for dry air equal to 287.058 J/(kg.Input the calculated values into the following formula:.Subtract the vapor pressure from the total air pressure to find the pressure of dry air: pd = p - pv.Find the actual vapor pressure, multiplying the saturation vapor pressure by the relative humidity: pv = p₁ * RH.If you are curious, check "FUNCTION ESW(T)" in the provided link). Saturation vapor pressure is the vapor pressure at 100% relative humidity (our calculator uses a more accurate, but also way more complicated equation that we didn't want to show here. Calculate the saturation vapor pressure at given temperature T using the formula p₁ = 6.1078 * 10^, where T is measured in degrees Celsius.Combining these two values gives you the desired parameter. You have to divide the pressure exerted by the air into two partial pressures: of the dry air and of the water vapor. The method of finding the air density is quite simple. Dew point is the temperature below which the water vapor starts to condensate, in ☌. 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. This is simply the outside temperature in ☌. If the analyzed location is at a high altitude, you can use our air pressure at altitude calculator to establish a more accurate value for this parameter. The barometric pressure expressed in hPa. You can usually find them on your local weather stations website. To find the air density at any given location, you will need some basic weather parameters. As a rule of thumb, you can expect a drop of 0.0022-0.0023 lb/cu ft (0.035-0.036 kg/m³) per 1000 ft of altitude change. If you change the air temperature, humidity, or the altitude (and hence the pressure), the air density will change, too. One exceptions is water vapor the more water vapor in the air, the lower its density.įor dry air, its density at sea level at 59 ☏ (15 ☌) and 14.7 psi (1013.25 hPa) (mean sea-level pressure), is approximately 0.0765 lb/cu ft (1.225 kg/m³). Most components have similar densities and don't influence the overall density in a substantial way.
However, the air will cease to be dry air when water vapor appears.Īs a mixture of gases, air doesn't have a constant density this value depends largely on air composition. The remaining 1 % contains many different gases, among others, argon, carbon dioxide, neon or helium. Dry air mostly consists of nitrogen ( ~78 %) and oxygen ( ~21 %). The density of air is usually denoted by the Greek letter rho, or ρ, and it measures the mass of air per unit volume (e.g. You might also want to check out our speed of sound calculator which is a tool that helps you calculate the speed of sound in dry air and water at any temperature. In the following text, you will find out what is the air density at sea level and the standard air density. Therefore, air pressure decreases with increasing altitude. It is easy to imagine that the higher you stand, the less air is above you and the pressure is lower (check out our definition of pressure!). The air pressure can be related to the weight of the air over a given location. It mainly changes with temperature, relative humidity, pressure and hence with altitude (take a look on the air density table below). The density of air depends on many factors and can vary in different places. Continue reading to get a better understanding of the relationship between the local weather and ρ, and learn what air density levels you can expect in various regions. This value is vital for many further calculations, such as determining the aerodynamic drag forces or the performance of wind turbines. This physics calculator is designed to help you determine either the density, volume or mass in case two out of the three variables are known.Use this air density calculator to instantly find how tightly packed an object's molecules are, allowing you to estimate ρ (air density) basing on the local temperature and pressure conditions.
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