REV.CHIM.(Bucharest) 70No. 4 2019 http:www.revistadechimie.ro 1187Influence of Thermal Comfort on Health [616017]

REV.CHIM.(Bucharest) ♦70♦No. 4 ♦2019 http://www.revistadechimie.ro 1187Influence of Thermal Comfort on Health
CARMEN OTILIA RUSANESCU1, MARIN RUSANESCU2*, COSMIN JINESCU3*, GIGEL PARASCHIV1
1 University Polytechnic, Faculty of Biotechnical Systems Engineering, 313 Splaiul Independentei, 060042 Bucharest, Romania
2V alplast Industrie 9 Preciziei Blv., 062202, Bucharest, Romania
3*Politehnica University of Bucharest, Faculty of Mechanical Engineering, 313 Splaiul Independentei , 060042, Bucharest,
Romania
The purpose of this paper is to estimate the conditions of human comfort in Bucharest. To describe the
influence of the climate on human health, several indices have been developed describing the degree of
physiological comfort offered by the meteorological conditions, taking into account meteorological
parameters registered daily by the weather station at the Polytechnic University of Bucharest, Faculty of
Biotechnical Systems Engineering: temperature and relative air humidity, wind speed. The following indices
were analyzed: summer SCHARLAU index (ISE), winter SCHARLAU index (ISH), thermohigrometric index
(THI), wind cooling power (skin stress index) (P), temperature equivalent to cooling wind power Tpr, to
determine the influence of thermal comfort on health.
Keywords: thermal comfort indices, wind cooling power
Climate has a direct impact on people’s lives and health.
The measured values of the meteorological parameters
are perceived differently by the human body due to theparticular physical condition of the persons and the weather
conditions. Depending on the air temperature, the wind
may cool, suffocate or dull. It is necessary to know thelimitations imposed by bioclimate on the human body, from
a practical and theoretical point of view [4]. The analysis
of the evolution and distribution of atmospheric parametersimpacting the human body is of interest to the capital city
of Bucharest with a population of approximately 1884
million inhabitants. Knowledge particularities bioclimaticof Bucharest is fully justified, even if we refer only to the
significant number of people living in this region as well as
tourists, under the specific bioclimatic conditions.
To describe the influence of thermal comfort on human
health, several indexes have been developed describing
the degree of physiological comfort offered by themeteorological conditions, taking into account different
parameters (relative air temperature and relative humidity,
wind velocity) as measured by weather station sensorsfrom Politehnica University of Bucharest, Faculty of
Biotechnical Systems Engineering, sensors made of
corrosion resistant materials in accordance with
environmental legislation [7, 10, 12, 16-18, 26-29, 31, 32,
33]. Climate conditions influence the comfort of organisms
[22]. All organisms, including humans, it adapts in time toclimatic conditions, but the variation or tendencies of
increasing and decreasing certain parameters can induce
additional stress. To highlight the climate favorability inBucharest, bioclimatic indices were analyzed: summer
SCHARLAU index (ISE), winter SCHARLAU index (ISH),
thermohigrometric index (THI), wind cooling power(cutaneous stress index), the temperature equivalent to
the cooling wind power T
pr.
The climate is favorable to the activities throughout the
year. The summer sun during the cold period causes
excessive heat (sunstroke, hyperthermia, dehydration),
sometimes associated with other associated side effectssuch as urinary or renal infections caused by insufficient
hydration or excess water renal elimination. Ultraviolet
radiation can cause: melanoma, eye disease (cataracts),sunstroke, sunburn. When the thermometer get down under
* email: rusanescum@yahoo.com, cosmin.jinescu@yahoo.com-4 degrees Celsius, the risk of heart attack increases. Thecold is also dangerous for people suffering from respiratoryfailure. Defects occur when exposure to low air
temperatures. Hypothermia builds up after prolonged
exposure to cold when body temperature falls below thethreshold of minimally admitted domestic (-37
0 C). In this
situation, the body begins to react violently: chills get
maximum intensity. Pulmonary diseases have a higherdegree of occurrence in autumn and winter when relative
humidity exceeds 50% and wind speed is lower. Also during
this period there are sudden cooling associated with thedecrease of the atmospheric pressure. The most common
disease is the cold that occurs due to the low immunity of
the body. Flu and influenza is common in September, witha peak occurring in the winter months (December).
Pneumonia usually occurs due to sudden heating in the
cold season.
Experimental part
Materials and methods
Summer SCHARL AU Inde x (ISE)
The summer Scharlau index describes a bioclimatic
thermal comfort when temperature values are higher than0
0C, as the values decrease, the more intensive the heat
discomfort (table 1). Calculation of summer SCHARLAU is
achieved by considering that at a certain critical value ofrelative humidity corresponds to a critical limit value of air
temperature over which, in the absence of wind, the human
body begins to feel the feeling of discomfort by heatingdue to unfavorable bioclimatic conditions (wet heat) [1-
3].
The summer Scharlau index can only be calculated for
relative humidity values higher than 30% and air
temperature between + 17
0C and + 390C. Temperatures
below + 17 ° C describe a relative bioclimatic comfortstate, and higher than + 39 ° C, cause an increased
discomfort [3,4].
For the calculation For the SCHARLAU estival (ISE),
calculate the appropriate critical temperature (T
c) value
according to the logarithmic equation:
Tc = [-17,089 * Ln (U)] +94.979 (1)

http://www.revistadechimie.ro REV.CHIM.(Bucharest) ♦70♦ No. 4 ♦2019 1188where: Tc critical temperature (°C); U relative air humidity
(%)
The summer SCHARLAU (ISE) value (expressed in units)
is given by the difference between the critical temperature
(Tc) and the local temperature (air temperature measured
on the dry thermometer) (Tusc):
ISE = Tc – Ta(2)
This temperature difference can be: positive when the
local temperature does not exceed the critical temperature,
there is no discomfort; negative when the localtemperature exceeds the critical temperature, causing
discomfort by heating [30].
The Scharlau index has two variants: the Summer
Scarlau Index (ISE) and the Winter Scharlau Index (ISH)
[5].
Table 1
THE SUMMER SCHARLAU INDEX -ISE (UNITS) AND CRITICAL
TEMPERATURES (0C) [5]
SCHARLAU winter index (ISH)
Reflects the level of human discomfort caused by
cooling. Associated critical temperatures are the
corresponding air temperature values below which, in theabsence of wind, the human body feels discomfort due to
cooling due to unfavorable bioclimatic conditions (wet
cold) [5]. The Scharlau hibernal index can only becalculated for relative humidity values higher than 40% and
air temperature between -5°C and + 6°C. Temperatures
above + 6°C describe a relative bioclimatic comfort state,and the lowest of – 5°C, create a state of discomfort [3].
For calculating the SCHARLAU Hybernal Index (ISH),
the corresponding critical temperature (T
c) value must be
calculated according to equation:
Tc = (0.0003 * U) + (0,1497 * U) – 7.7133 (3)
where: U – relative air humidity (%); Tc – critical temperature(° C)
The winter SCHARLAU (ISH) (expressed in units) is
calculated by the difference between air temperature and
critical temperature (Tc), according to the relationship
(4):
ISH = Ta – Tc(4)
This temperature difference can be: positive when the
local temperature is higher than the critical temperature,
which does not cause discomfort, negative when the localtemperature is lower than the critical temperature, which
causes cooling discomfort. The classes of values
corresponding to the Winter Scharlau index are shown intable 2.Thermohygrometric index (THI)
THI is calculated based on air temperature and relative
humidity. The formula used to determine this index is [6, 8,
9, 11]:
THI [p C] = Tusc – (0.55 – 0.0055 * UR)*(Tusc – 14.5) (5)
where: Air temperature [°C] to dry thermometer; UR relativehumidity [%].
Using this index can be classified conditions and types
of climate, for hot and cold weather [11].
Table 2
VALUE CLASSES FOR ISH [3, 5]
Table 3
THRESHOLDS OF THI
VALUES FOR
DIFFERENT TYPES OF
BIOCLIMATES [14, 15]
Wind Cooling Power (Skin Stress Index)
The human body, through its exposed parts (skin),
comes in direct contact with the terrestrial atmospherewhose parameters (brightness, radiation, temperature,
humidity, wind) require it to adapt to the meteo-climatic
complex by triggering thermolysis or thermogenesis. Insome situations thermoregulation is not required.
In 1974, Becancenot, the wind cooling power formula
that takes into account two weather-climatic parameters:air temperature and wind speed. It is a meteoro-
physiological concept that expresses in objective terms
the combined action of air temperature and wind speedon the caloric balance of the human body. The calculation
formula for the wind cooling power is:
(6)
where: P the cooling power [kcal/m2/h], v the wind speed
[m/s], the air temperature conventionally reported at the
33 [0C]. V alues of wind cooling power, assigned to classes,
have been determined, depending on the reactions of the
human body, with indices of comfort or discomfort with
different values and signs (negative, null or positive). Theseare called cutaneous stress indexes. They return the

REV.CHIM.(Bucharest) ♦70♦No. 4 ♦2019 http://www.revistadechimie.ro 1189character of time / climate, but also the degree to which
the human body is subjected to stress induced by the loweror higher values of the wind cooling power [19]. The wind
cooling power (kcal/m
2/h) and the significance of the
cutaneous biostress index is shown in table 4 [23].
The temperature equivalent to wind cooling power TprThe wind cooling power index is completed by the
temperature equivalent to the wind cooling power Tpr. This
is the temperature the air would reach at certain wind
speeds. The calculation formula for Tpr, [20, 25] is given by
the relationship:
(7)
Tc temperature equivalent to cooling wind power [0C],
Tusc air temperature measured at dry thermometer [0C], v
wind speed [m/s].
The value ranges of P correspond to intervals with
certain values of Tpr. The effects of P (and related Tpr) on
human physiology depend on the intensity of caloric lossessuffered by the human body.
Results and discussions
Summer SCHARLAU Index (ISE)
In figure 1 are highlighted calculations of the SCHARLAU
summer report.
By comparing the values obtained in figure 1 with the
values in table 1, during June, 2016, 2017, 2018, July 2010,
2011, 2017, 2018 and August 2018, values correspondingto the thermal comfort were obtained during most of themonths values between -1 and -3 were recorded, indicating
a moderate discomfort mainly due to an increase in
evaporation rate that prevents the human body fromeliminating excess heat inside so that the temperature of
the inner body increases, creating discomfort due to
overheating. August 2018 the discomfort class accentuatedthe value of -5.4. The rest of the analyzed period with
specific thermal comfort values.
SCHARLAU winter index (ISH)
Figure 2 highlights the calculations made for the winter
SCHARLAU index.
Comparing the values obtained with those in table 2
during the analyzed period in most months, values
corresponding to the increased discomfort (values lessthan or equal to -3) were obtained only in December 2011,
2015, 2016, 2017, February 2013, March 2018, November
2012, 2014, values ranging from -1 to -3 units wererecorded, indicating moderate discomfort.
Thermohygrometric index (THI)
According to the THI index thresholds (table 3) it can be
observed (fig. 3) that the corresponding values were
obtained as: cold, in all the analyzed years in the months:March, November, December, January 2009, 2010, 2011,
2012 , 2013, 2014, 2015, 2016, 2018, February only February
2012 very cold in January 2017 and February 2012. Conesin April 2009, 2010, 2017, October 2009, 2012, 2017.
Comfort in May in all years, April 2015 , 2016, 2018, June
2010, 2014, July 2013, September 2009, 2010, 2012, 2013,2014, 2016, 2017, 2018, October 2018.
Table 4
THE COOLING POWER OF THE
WIND [kcal/m2/h] AND THE
SIGNIFICANCE OF THE BIOSTRESS
INDEX SKIN [23]
Table 5
THE COOLING POWER OF WIND, EQUIVALENT
TO WIND COOLING POWER AND
PHYSIOLOGICAL EFFECTS INDUCED BY IT [20]
Fig. 1 V alues obtained for ISE in 2009-2018 Fig. 2 V alues obtained for ISH in 2009-2018

http://www.revistadechimie.ro REV.CHIM.(Bucharest) ♦70♦ No. 4 ♦2019 1190From the analysis of the monthly average values of the
THI index obtained on the basis of mathematical
calculations, it can be easily observed that the analyzedregion ranges between -3.6 ° C (February 2012) and +26.9
° C August 2016. According to the annual averages, notes
that the variation of the THI index is directly proportional totemperature rise or fall. The monthly average values of
the THI index show that, as a whole, the city of Bucharest
is maintained in a cold bioclimate, subjecting the humanbody to a higher calorie adaptation effort. In understanding
the causality of some behavioral aspects, the climate plays
an important role. Bioclimatic indicators have the role ofhighlighting the influence of climate on the human body.
The exciting steppe climate, specific to Bucharest, forces
the living organisms to adapt to low rainfall and very hightemperatures through warm and dry summers. These
adaptations take the form of a slight discomfort highlighted
by the bioclimatic indices analyzed. Bioclimatic discomfortis reflected in the occurrence of cardiovascular and
respiratory diseases, but also through behaviors
characterized by intolerance, violence and impulsiveness.
Wind Cooling Power (Skin Stress Index)
I calculated the skin stress index of formula (6)
according to the index analysis thresholds (table 4).
It is observed that during the summer the predominant
values are between 150-299 corresponding to stress bytriggering thermolysis, exerting on the human body a slight
discomfort, which requires heat loss (eg perspiration),
respectively thermolysis (fig. 5) May, August, all yearsanalyzed: May 2009, 2010, 2012, 2013, 2015, 2016, 2017,
2018, July 2009, 2010, 2011, 2013, 2014, 2015, August
2009, 2011, 2013, 2014.
In the coldest months, January, February, December,
the decrease in skin stress is moderately hypertonic.
Hypertonic stress by triggering thermogenesis in winterthe values of the index are between 600-823 (fig. 4),
January and February the analyzed period 2009-2018 less
January and February 2016, December 2016, 2017, 2018.
In March 2009, 2011, 2012 and April 2009, 2010, 2011,
2012, no thermoregulation is required.
The values are in the category of hypotonic stress, stress
by triggering thermolysis in summer values between 101-
144, July 2010, 2015, 2016, 2017, 2018, August 2010, 2012,
2015, 2016, 2017, 2018.
There is an increased skin stress in January and
relaxation in March, April, October, November (fig. 4). In a
very cold, strong wind, the stress index of the skin canreach high levels of wind cooling power, causing a very
high hypertonic stress with implications for the health of
the exposed person (fig. 4), which can cause rapid frostbiteof parts of the unprotected human body exposed to direct
air.Temperature equivalent to wind cooling TprTpr values ranging from 0 to 3.5 were in December and
January throughout the analyzed period, the stress is
expressed by the trend of dehydration in winter. Tpr index
values ranging from 4 to 7 were in March throughout the
analyzed period, the stress is expressed by the tendency to
dehydrate during cold weather. Balance values wereobtained in February, March 2016, November, December
2017, December 2015, 2015, 2017 (8.9-11.7). V alues
between 11.7-15.5 hydration in April 2009, 2010, 2011,2013, 2014, 2015, October 2009, 2011, 2013, 2016,
November 2015, 2017. In the other months of May –
Fig. 3 V alues obtained for THI in 2009-2018 Fig. 4 V alues obtained for P in 2009-2018
Fig. 5 Values obtained for Tpr in the years 2009-2018
September all the analyzed period obtained values
corresponding to the hydration according to table 3 and
figure 5.Conclusions
The analysis of the different comfort indices shows that
the bioclimatic conditions for Bucharest are comfortable.Based on daily data, summer is very pleasant for tourists,
for residents except for some warm summer months when
it was a moderate discomfort.
In the winter months, values were found to be consistent
with discomfort and moderate discomfort. According to
the skin stress index during the summer, the prevailingvalues are between 150-299 corresponding to the stress
by triggering thermolysis, exerting on the human body a
slight discomfort, which requires heat loss. There is anincreased skin stress in January and relaxation in March,
April, October, November. In a very cold, strong wind, the
skin’s stress index can reach a high level of wind coolingpower, causing a very high hypertonic stress with
implications for the health of the exposed person, which
can quickly cause frostbite of body parts unprotectedhuman exposed to direct atmospheric air. Skin stress is
low, about half of the year presenting a relaxing climate
from this point of view. Hypotonic stress, triggering summerthermolysis, is felt mostly in July and August. The
temperature equivalent to the wind cooling power ran for
the April – October period as one characterized by thermalcomfort; only January, the month with the lowest average
temperature and moderate wind speeds, is characterized
by more discomfort.

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Manuscript received: 14.12.2018