Environmental Science: Comprehensive Analysis of Humidity Parameters

This document presents a comprehensive analysis of humidity parameters, including specific humidity, relative humidity, and dew point temperature. The assignment involves detailed calculations using provided formulas and data, with a focus on understanding the relationships between temperature, humidity, and saturation vapor pressure. The solution includes filled tables and graphical representations, illustrating the correlation between these variables. Furthermore, it explores the impact of humidity on indoor environments, such as basements, and discusses factors influencing air flow and moisture levels. The assignment also covers the practical application of these concepts in various locations, along with the significance of wet bulb and dry bulb temperatures. Additionally, the document addresses water vapor calculations, mixing ratios, and the release of latent heat. The assignment references key environmental science literature.

Geography Lab: Humidity
SECTION A
1) Specific humidity is given by E= RH × Es
100
Where Estands for specific humidity (the real quantity of water present in the air),
RH is the relative humidity in g/Kg, Es is the saturation water vapor of the air in
millibars.
We get saturation water vapor by Es=6.11 ×10 × ( 7.5 ×T c
237.7+ Tc )
Where , Es is the saturation water vapor of the air in millibars, T c is the given
temperature in degrees celcius.
Es=6.11 ×10 × ( 7.5 ×30
237.7+ 30 )=1.9279 mb
From there we can now the saturation water vapor of the air is used to compute the
specific humidity (the actual amount of water vapor present in the air). This results into
the following:
E= RH × Es
100
E=( 75 ×1.9279 mb
100 )=1.4459 g/ Kg
2) Dew point temperature is given by T dc=−430.22+237.7 ×ln ( E)
−ln (E)+19.08
Where T dc is the dew point temperature in degrees celcius (℃), ln (E) is the natural
logarithm of the specific humidity (the actual amount of water vapor present in the air)
T dc =−430.22+ 237.7 ×0.3687
−0.3687+19.08 =−18.3087℃

3) Relative humidity can be found from E= RH × Es
100
Where Eis the specific humidity (the actual amount of water vapor present in the air),
RH is the relative humidity in g/Kg, Es is the saturation water vapor of the air in
millibars.
Dew point temperature is given by T dc =−430.22+ 237.7 ×ln ( E)
−ln (E)+19.08
Where T dc is the dew point temperature in degrees celcius (℃), ln (E) is the natural
logarithm of the specific humidity (the actual amount of water vapor present in the air)
This implies that −430.22+237.7 × ln ( E )=0
237.7 × ln ( E ) =430.22
ln ( E )= 430.22
237.7 =1.8099
E=e1.8099=6.1098
Saturation vapor pressure (Es) is given from (1) as
Es=6.11 ×10 × ( 7.5 ×T c
237.7+ Tc )
Where , Es is the saturation water in the air in millibars, T c is the given temperature in
degrees celcius.
We are given T c=20 ℃. Inserting this into the formula results into:
Es=6.11 ×10 × ( 7.5 ×20
237.7+ 20 )=0.9639 mb
Therefore relative humidity can be computed as:
Therefore relative humidity
RH = 100× E
Es
RH = 100× E
Es
= 100× 6.1098
0.9639 =633.8624 %

Where Eis the specific humidity (real quantity of water present in air),
RH stands for relative humidity in g/Kg, Es is the saturation water vapor of the air in
millibars.
4) Filling the table
SAMPLE TEMPERATURE (℃) RELATIVE
HUMIDITY
ACTUAL SPECIFIC
HUMIDITY (g/Kg)
DEW
POINT (℃)
RANK
A 15 90% 24.4811 20.7731 1
B 22 60% 23.2919 19.9652 2
C 26 40% 18.0728 15.9264 4
D 30 45% 23.1093 19.8375 3
E 35 30% 17.6444 15.5509 5
This table has been filled by use of the following formulas
Dew point temperature is given by T dc =−430.22+ 237.7 ×ln ( E)
−ln (E)+19.08
Where T dc is dew point temperature in degrees celcius (℃), ln (E) is natural logarithm
of the specific humidity ( genuine quantity of water vapor existent in air).
Relative humidity can be found from E= RH × Es
100
Where Eis the specific humidity (the actual amount of water vapor present in the air),
RH stands for relative humidity in g/Kg, Es is the saturation water moisture of air in
millibars .
TABLE 1.
Temp(˚C) -40 - -20 - 0 5 10 1 20 25 30 35 40

30 10 5
Humidity
(g/kg)
0.1 0.3 0.7
5
2 3.5 5 7 1
0
14 20 26 35 47
Curve representing the variables in Table 1. We plotted saturation relative humidity against
temperature.
Figure 1: This is the that figure plots the values of table 1. This figure is showing the saturation
specific humidity against temperature.
5) Relative humidity is important measure for cooling and heating purposes during summer.
Outdoor relative humidity climbs, there is no enough perspiration to cool the skin. Cold
air sinks and the hot air rises, the basement of my house is generally the coldest place in
the house. The saturation specific humidity drops, when temperature of warm humid air
drops and sinks into the basement. However, temperature must drop to the dew-point
temperature level, for actual specific humidity to remain the same, so that relative
humidity increases.
Humidity levels in the besement air, soil, outdoor locations and first floor are strongly
intercorrelated. Models of linear reversion models showed that humidity from outside

locations indirectly, and directly from other zones, explain about 70% of general
deviation in basement humidity stages. Flow of air-borne humidity springs and vault
humidity have shown that all houses experience large variations in interzonal ventilation
and air flows, and that active soil depressurization (ASD) process accelerates flow of
upstairs and outdoor air into subterranean vault. ASD process practically eradicated
minor, pre-existing movement of moisture and air from soil, which can be extra vital
source in houses with higher soil gas entrance. Minor moisture stages in upstairs air in
summer and outdoor air in the winter have impending to help drying basement or
offset moisture entry from other sources. It has also been shown that ASD or block wall
depressurization (BWD) can have a complex merital impact on humidity and
circumstances for progression of microorganism around microbial growth in and around
the finish floors and constituents applied to underground room walls that are
microclimate humidity sensitive (Turk & Hughes, 2009).
SECTION B
Location T(dry) (℃
)
T(wet) ( ℃
)
WBD (℃) RH(%) Dew Point q (kPa) qs (Pa)
Outdoor 5.1 4.5 0.6 5.04 -13.892 8.8055 1.7471
Corridor 22.5 16 6.5 49 12.3 750.4363 15.3061
Class 23 19 4.0 69 16.8 1482.6628 21.4879
Cafeteria 23 14 9.0 37 10.4 429.6190 11.6113
The dew point, wet bulb and dry bulb temperatures are vital on determining state of vapor in the
atmosphere. Having knowledge on two of these measurements can help in determination of the
state of the relative humidity. This includes the content of water vapor in the air and latent heat
of the air.

To get wet bulb depression (WBD) you need to compute;
WBD=(Dry bulb temperature) –(wet bulb temperature)
Relative humidity is computed by dry bulb temperature.
The relative humidity (RH) has been obtained from the table of relative humidity (Peters, 2013;
“Relative Humidity Table,” n.d.), and the curve in section A.
The dew point is computed using the equation T dp ≈ T − 100−RH
5
Where T is dry bulb temperature, RH is relative humidity.
Assume total pressure of moist air to be 100 kPa and the relative humidity is measured as 37 g
kg-1 partial density of moisture in the atmosphere can be calculated as.
Assume molecular weight of water to be 18, and of air to be 29
Water mole fraction is 0.037
18 ( 1
29 + 0.037
29 )=0.004296
Water vapor becomes 0.004296 ×100 kPa=0.4296 kPa
Relative humidity (RH) is defined as the partial vapor pressure of air q to partial vapor density of
saturated air (Arnold, 1965).
RH = q
qs
Therefore partial vapor pressure of saturated air ( qs) is provided by. qs= q
RH
While the partial vapor pressure of air q is given by q ¿ RH × qs

The relative humidity is normally expressed in percentage form as ¿ q
qs
100
Figure 2: This is the figure of the same values in section A that helped us fill in the table in part 1
of section B. This figure is showing the saturation specific humidity against temperature.
2) Water vapor is measured by relative humidity in relative to air temperature. This means it is
degree of water suspension that can exist in the atmosphere in comparison to actual amount of
water in the air at the same temperature (Gareth, 2000). That is why warm air contains more
moisture than cold air (in our case study the cold environment was the outdoor while all the
others were warm locations). Therefore at the same specific humidity, air will contain lower
relative humidity if it is cooler and a higher relative humidity if the it is warmer (Nivaldo, 2015) .
Therefore what we experience in the outdoor location is the absolute humidity in the air.
SECTION C
1) Water vapor is 2000 g, dry air mass is given as 200 Kg
i) The specific humidity is the water vapor quantity per unit mass of saturated air,

q= mv
md +mv
= 2000
200+2 =2000
202 =9.9010 g /Kg
Where mv = mass of water vapor, md +mv is the mass of the moist air
ii) Mixing ratio is water vapor mass per unit mass of dry air.
q= mv
md
= 2000
200 =10 g / Kg
2) Use table 1 to determine the parcel air temperature
From the table we can easily deduce that the parcel air temperature is given by:
Temperature = 15 ℃
3) Latent heat is released to the air is given by
∆ Q=∆ mL=2000 g(2.5 ×103 J / g)=5.0 ×106 J
Where ∆ Q is the latent heat released to the air, ∆ m is the change in mass in grams, L is
the latent energy released on condensation
4) When 5.0 ×106 J of energy is supplied to heat 1 g of dry air , then the change in heat is
given by ∆ T = ∆ Q
mC p
= 5.0 ×106 J
2000 g ×1.01 J /(g ℃) =2475.2475 ℃
∆ T is the change in temperature, ∆ Q is the latent heat released to the air, m is the mass I
grams, C p is the specific heat of dry air.

References
Arnold, W. 1965. Humidity and Moisture : Principles and methods of measuring humidity in gases.
London .Reinhold Publishing Cooporation.
Gareth, N. 2000. Weather File; GHC. New York. Nelson Thornes Publishing
Nivaldo, J. 2015. Chemistry in Focus : A Molecular View of Our World. 6th ed. Singapore :
Cengage Learning.
Peters, R. T. (2013). Direct Calculation of Thermodynamic Wet-Bulb Temperature as a Function
of Pressure and Elevation Direct Calculation of Thermodynamic Wet-Bulb Temperature as
a Function of Pressure and Elevation, (January). https://doi.org/10.1175/JTECH-D-12-
00191.1
Relative Humidity Table. (n.d.), 44.
Turk, B., & Hughes, J. (2009). Movement and Sources of Basement Ventilation Air and
Moisture During ASD Radon Control Additional Analysis by.