relative humidity

(redirected from Relative air humidity)
Also found in: Dictionary, Thesaurus, Encyclopedia.
Related to Relative air humidity: absolute humidity, Specific humidity


the degree of moisture in the air.
absolute humidity the actual amount of vapor in the atmosphere, expressed in milligrams per liter.
relative humidity the percentage of moisture in the air as compared to the amount necessary to cause saturation, which is taken as 100.
humidity therapy the therapeutic use of water to prevent or correct a moisture deficit in the respiratory tract. Under normal conditions the respiratory tract is kept moist by humidifying mechanisms that allow for evaporation of water from the respiratory mucosa. If these mechanisms fail to work, are bypassed (such as with an endotracheal tube), or are inadequate to overcome the drying and irritating effects of therapeutic gases and mucosal crusting, some form of humidification must be provided.

The principal reasons for employing humidity therapy are: (1) to prevent drying and irritation of the respiratory mucosa, (2) to facilitate ventilation and diffusion of oxygen and other therapeutic gases being administered, and (3) to aid in the removal of thick and viscous secretions that obstruct the air passages. Another important use of water aerosol therapy is to aid in obtaining an induced sputum specimen.

Humidity therapy may be delivered in a variety of ways. Humidifiers and vaporizers increase the water content of an environment and are limited to the treatment of upper respiratory disorders because they produce particles that are too large to penetrate deeply into the lungs. Nebulizers generate clouds or mists of particles that are extremely small and thus capable of penetrating more deeply into the bronchioles and small structures of the lower respiratory tract. Examples of these include jet instruments and ultrasonic nebulizers.

rel·a·tive hu·mid·i·ty

the actual amount of water vapor present in the air or in a gas, divided by the amount necessary for saturation at the same temperature and pressure; expressed as a percentage.

relative humidity (r/h)

the amount of moisture in the air compared with the maximum the air could contain at the same temperature.

rel·a·tive hu·mid·i·ty

(rel'ă-tiv hyū-mid'i-tē)
The actual amount of water vapor present in the air or in a gas, divided by the amount necessary for saturation at the same temperature and pressure; expressed as a percentage.

rel·a·tive hu·mid·i·ty

(rel'ă-tiv hyū-mid'i-tē)
Actual amount of water vapor present in air or gas, divided by amount necessary for saturation at same temperature and pressure; expressed as a percentage.
References in periodicals archive ?
Moreover, the air supplied from the dehumidifier in the separated system only caused a local reduction in the relative air humidity value, but on a larger part of the cross-section than the supplied air in case 1.
Relative air humidity in the tribune zone was in the range of 30/32% and 31/34% in cases 1 and 2 respectively.
Correlations of horse's vital parameters at rest and ambient temperature, relative air humidity and air pressure were analysed using Spearman correlation coefficient (r).
1 Results of heart rate, respiration rate and body temperature measurements as a function of relative air humidity, air temperature and atmospheric pressure in the rest period
Other attributes, like relative air humidity and noise isolation should be minimized.
From the definitions, it is evident that relative air humidity indicates how far the condition of the air in question is from dew point, i.
The relationship between pollen dispersal and meteorological conditions was studied using daily average meteorological data (air temperature, relative air humidity, amount of precipitation and wind velocity) for the period 2004-2009, provided by the Lithuanian Hydrome-teorological Service (LHMS).
Our results regarding relative air humidity and light intensity are within ranges specified for appropriate animal care (UL.
1[degrees]C, relative air humidity error [+ or -]2%) at the suction hole of the ventilator, in the constant static pressure chamber of the drying rig and in the layers of Hyssopi herba.