relative humidity

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Related to Relative air humidity: absolute humidity, Specific humidity

humidity

 [hu-mid´ĭ-te]
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.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

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.
Farlex Partner Medical Dictionary © Farlex 2012

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.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

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.
Medical Dictionary for the Dental Professions © Farlex 2012
References in periodicals archive ?
Finally, temperature influence and relative air humidity are factors that have a direct effect on the behavior grazing animals at different periods of the year (McMANUS et al., 2009).
For each test, the parameters of the environment in which the samples were conditioned for 7 days were 20[degrees]C [+ or -] 2[degrees]C and a relative air humidity of 65 [+ or -] 5 percent, which prevented changes to the wood moisture content (hereinafter referred to as the standard environment).
Treatment Lower irrigation Higher irrigation Lower temperature LTLW LTHW Higher temperature HTLW HTHW Table 2: Climatic conditions represented by temperature and relative air humidity during day (5 am-9 pm; n = 1020) and midday (11 am-2 pm; n = 60) in greenhouses 1 and 2 in June 2014.
Pork kabanosy dried in chambers with a relative air humidity of 70 and 60% were characterized by significantly (p < 0.05) lower levels of yellow color ([b.sup.*)] in the cross sections of the bar compared to kabanosy dried at a relative air humidity of 80% (Table 2).
Relative air humidity in the tribune zone was in the range of 30/32% and 31/34% in cases 1 and 2 respectively.
3.1 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
According to the related work on indoor air, seven attributes were selected: air exchange ([m.sup.3]/h), relative air humidity (percents), air temperature (C), air velocity (m/s), surface area to volume ratio (1/m), noise isolation (dB) and annual heat requirement (kWh/m2/year).
Relative air humidity as a criterion of air quality should, thus, be taken into account in the evaluation of the hygrother-mal microclimate.
2 and, in the absence of relative air humidity data, the value of [e.sub.a] (actual water vapor pressure in the atmosphere) was estimated by Eq.
For traditional procedure of the accelerated aging (AA) test, 18g of seeds per lot were distributed in a single layer on a stainless steel mesh inside transparent acrylic boxes (11x11x3.5cm), containing 40mL of distilled water, resulting in an internal relative air humidity of approximately 100%.
The following environmental variables were measured for each of the quadrats in a plot: litter depth, atmospheric temperature (maximum, average and minimum), soil temperature, relative air humidity (maximum, average and minimum), luminosity, canopy closure, litter moisture (leaf and branch), number of individuals and morphotypes of herbaceous plants up to 50 cm height, number of individuals and morphotypes of individuals of herbaceous plants up to 50 cm height (Menez, 2002).
Relative air humidity was between 63 % and 66 %, and these values met regulations for animal care (60-80%) (Animal law, 2007).