Human Humidity

Mechanical Hygrometers Materials such as human hair, wood fiber, and plastics have been used to measure humidity. These methods rely on a change in dimension with humidity. 

Humans are sensitive to moisture and can reliably describe the humidity of the environment using word scales as demonstrated in Fig. 5.12. The subject s humidity judgments appear to be functions of the air s dew point, a measure of absolute humidity, and are relatively unaffected by the ambient temperature. Further, people are also good at perceiving skin moisture, as illustrated in Fig. 5.13, where perceived skin wettedness is seen to correlate well with measured skin wettedness. 

ETA 1 Air of the same qualit> as outdoors with respect tr> humidity. From rooms with pollutant sources from humans and building mtiterinl. Offices, storage rooms, public service places. No major pollution sources, including smok ing. 

Human occupants, electrical/electronic equipment and process plant all emit varying quantities of sensible and latent heat. Equally, these various elements require (or can tolerate) differing environmental conditions. Depending on these operational constraints, the need may well exist to provide natural (or powered) ventilation to maintain environmental conditions (temperature and/or humidity) consistent with the occupational/process requirements. 

Where human occupancy or wet process plant is present, the emission of water vapor will occur. Depending on external conditions and building fabric constmction, the attendant potential for excessive ambient humidity or surface condensation may exist. 

Atmospheric aerosols have a direct impact on earth s radiation balance, fog formation and cloud physics, and visibility degradation as well as human health effect[l]. Both natural and anthropogenic sources contribute to the formation of ambient aerosol, which are composed mostly of sulfates, nitrates and ammoniums in either pure or mixed forms[2]. These inorganic salt aerosols are hygroscopic by nature and exhibit the properties of deliquescence and efflorescence in humid air. That is, relative humidity(RH) history and chemical composition determine whether atmospheric aerosols are liquid or solid. Aerosol physical state affects climate and environmental phenomena such as radiative transfer, visibility, and heterogeneous chemistry. Here we present a mathematical model that considers the relative humidity history and chemical composition dependence of deliquescence and efflorescence for describing the dynamic and transport behavior of ambient aerosols[3]. 

C05-0098. In the tropics, water will condense in human lungs when the temperature and relative humidity are too high. Using Table 5-4. estimate the vapor pressure of water at body temperature of 37 °C. If atmospheric temperature is 40 °C, at what relative humidity does this life-threatening process... 

In addition, the use of field fortification samples measures the carefulness factor of the Field Scientist during the field research and allows a Study Director/Manager or distant observer to obtain a quality control estimate on the field portion of the study. For this reason, the field fortification samples are usually meant to be different from laboratory procedural fortifications and are meant to be prepared under field conditions, which are considerably more rigorous than are controlled laboratory conditions. For example, environmental factors such as heat, humidity, wind, human stress, and other human factors such as fatigue to the Field Scientist are an integral part of any field worker exposure/re-entry study. Field fortifications made to matrices under these conditions will test and readily demonstrate the ability of the Field Scientist to perform such a difficult study under trying circumstances. 

Good ventilation in buildings is essential to minimise the incidence of pneumonia. Buildings that seem exposed by human standards are much healthier for cattle than those with a stuffy atmosphere. Stale, humid air, laden with dust, is a recipe for enzootic pneumonia. 

It is known that pesticide aerosols, formed when the pesticide steam settles on surfaces of miniscule droplets of water, are much more toxic than the steam form of the same pesticide. This circumstance turned out to be extremely important. Table 2.2 gives an idea of how dangerous pesticides are to humans when we ignore the role of factors such as atmospheric humidity. Data from... 

The natural composition of obsidian includes very little water, generally less than 0.1%. When new obsidian surfaces are created, either by the natural breakdown of obsidian bulks or by human activity, the exposure of a new surface to humidity in the air or to water brings about a process known as hydration the surface adsorbs (takes up) water and becomes... 

Our results suggest that forest degradation is detectable not only in Yungas but also in Chaco. In environments similar to Chaco, discrepancies between these results (lower) and estimations made in similar environments in other forests of the world might be due to structural differences, altitude, latitude and humidity, gradients (24, 32, 33). However, in our case the level of degradation exerted by human activity in this environment might also be responsible for the discrepancies [20, 21, 41] (further details refer to [43]). 

Tu and Knutson (1984) also measured the particle deposition of hydrophobic and hygroscopic particles in the human respiratory tract. They showed that the hygroscopic particles grow by a factor of 3.5 to 4.5 at the saturated humidity present in the lung. For the purpose of calculating bronchial deposition for a hygroscopic aerosol we assume an increase in size by a factor of 4 upon entry into the bronchial tree. 

Terrestrial plants take up nickel from soil primarily via the roots (NRCC 1981 WHO 1991). The nickel uptake rate from soil is dependent on soil type, pH, humidity, organic content, and concentration of extractable nickel (NAS 1975 WHO 1991). For example, at soil pH less than 6.5 nickel uptake is enhanced due to breakdown of iron and manganese oxides that form stable complexes with nickel (Rencz and Shilts 1980). The exact chemical forms of nickel that are most readily accumulated from soil and water are unknown however, there is growing evidence that complexes of nickel with organic acids are the most favored (Kasprzak 1987). In addition to their uptake from the soils, plants consumed by humans may receive several milligrams of nickel per... 

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