Quality of the Indoor Environment in Elderly Care Centers in Two Cities in Central Portugal: Viseu and Covilhã

Assessments of Indoor Environment Quality (IEQ) present a very significant challenge when analyses are undertaken mainly in buildings that include a particularly sensitive and vulnerable population, such as elderly people. In order to maintain an indoor environment that is adequate for occupants, it is necessary to comply with a set of requirements (for TVOC, the Portuguese threshold values) regarding concentrations of airborne pollutants and hygrothermal comfort conditions. This paper studies IEQ in compartments in 3 buildings in two cities in central Portugal, Viseu and Covilhã, which hold elderly care centers. The following environmental parameters were continuously recorded: air temperature, relative humidity, concentration of carbon dioxide, formaldehyde, and total volatile organic compounds and ventilation rates. An analysis of the obtained results was performed, taking recommended guidelines and threshold values into account, thus making it possible to evaluate the IEQ conditions and hygrothermal comfort in the selected indoor spaces. On the basis of the conclusions reached and the observed problems of hygrothermal comfort and indoor pollutants in the indoor spaces, a number of recommendations are proposed, specifically in terms of climate control, ventilation, and maintenance, in order to obtain an overall improvement of IEQ.


Introduction
In developed countries, people spend more than 90% of their time indoors. Indoor environmental conditions are strongly related to health, well-being, and overall performance [1]. With people spending so much time inside buildings, the issue of Indoor Environment Quality (IEQ) becomes especially important; therefore, a set of functional requirements exist to provide increased occupant comfort. In addition to the need to satisfy occupants' comfort requirements, special attention must be paid to their health, since inadequate IEQ can negatively influence the occupants' quality of life, affecting their health status.
Although IEQ plays an important role in all types of buildings, particular consideration should be paid to Elderly Care Centers (ECC). The perception of the elderly as a risk group with regard

City of Viseu
Portuguese thermal regulations [17] indicate approximately 1700 heating degree days (base 18 °C) for the town of Viseu, with an average elevation of 480 m.
A physical characterization of the two buildings and some of the compartments studied is presented in Table 1, which shows that they were constructed at quite different times and in different locations, and feature dissimilar characteristics and technical installations.

City of Viseu
Portuguese thermal regulations [17] indicate approximately 1700 heating degree days (base 18 • C) for the town of Viseu, with an average elevation of 480 m.
A physical characterization of the two buildings and some of the compartments studied is presented in Table 1, which shows that they were constructed at quite different times and in different locations, and feature dissimilar characteristics and technical installations. According to the regulations in Portugal [18], the minimum area of living rooms should respect a ratio of 2 m 2 /resident. In the case of ECC 2, this ratio is grossly disregarded.
Information about the interior cladding of the studied compartments, windows, and corresponding indoor and outdoor solar protection is presented in Table 2. A physical characterization of the studied building (ECC 3) and compartments is presented in Table 3. Information about the interior cladding of the studied compartments, windows, and corresponding indoor and outdoor solar protection is presented in Table 4.

Regulatory Requirements, Standards, and Experimental Conditions
The protective thresholds for the considered physico-chemical pollutants are set out in Table 5. Notes: a Value obtained for the molar mass of isobutylene [24]; b Margin of tolerance and protection threshold in existing buildings and new buildings without mechanical ventilation systems; for a mean of 8 h; c MT is the value added to "Protection threshold in new buildings" to get "Protection threshold in existing buildings and new buildings without mechanical ventilation", e.g., for TVOC: 0.6 mg/m 3 × 100% = 1.2 mg/m 3 .

Experimental Conditions in the City of Viseu
Measurements of exterior temperature were obtained from [25]. Regarding the location chosen for placing the equipment inside the compartments, places were avoided, whenever possible, that could influence the measurements of the indoor environmental parameters, such as windows and climate control equipment. The ACH was assessed using the decay technique, using metabolic CO 2 as a tracer gas (in post-occupancy periods), as described in ASTM E741 [26] and ASTM D6245 [27]. In Portugal, one of the supporting documents for testing is Technical Note TN-SCE-02, 2009 (ADENE-Portuguese energy agency), which, in Annex 3, allows the use of "Photonionization Detectors" (PID) as a monitoring method for TVOC and formaldehyde measurement [24]. Thus, such equipment was used in both cities.
The measurements of pollutants were carried out continuously in the rooms. They were performed during the period of occupancy [7:30 a.m. to 7:30 p.m.] in the living rooms. In view of the available equipment, only one point of analysis of the various parameters in each compartment was considered [24].
Two trials were conducted: the first in winter, i.e., between December 2015 and January 2016, and the second in spring, i.e., between March and April 2016. Table 6 presents the parameters, measuring instruments, and the main conditions of measurement.

Experimental Conditions in the City of Covilhã
Outdoor temperature measurements were obtained from a meteorological station at the University of Beira Interior (UBI), located at approximately 680 m altitude. Regarding the location chosen to place instruments inside the compartments and to assess the ACH, the criteria already presented were followed.
The measurements of the pollutants were performed continuously; each reading was measured over a minimum period of 5 min [24]. Due to the limitations of the instruments, the measurements of formaldehyde were punctual, although a maximum of 3 measurements, taken at 5 min intervals, was obtained. The first trial took place in February and June 2014, and the second in April and May 2015.
The minimum number of analysis points for the various indoor air quality parameters to be measured was calculated by applying the following expression to the total area of the compartment, rounding up to the unit [24]: where N i is the number of measurement points in zone i and A i is the area of zone i (m 2 ). Table 7 shows the minimum number of measurement points calculated.  Table 8 shows the parameters, measuring instruments, and the main conditions of measurement. In all presented results (cities of Viseu and Covilhã), the calculated mean (µ) refers to the arithmetic mean.

Presentation and Critical Analysis of Results
In the analysis of the results, according to Table 5, the following situations of discomfort and levels of pollutants were considered inadequate and excessive (the ECC analyzed were considered to be existing buildings [19]): (1) Percentage of time analyzed greater than or equal to 20% in the case of T int outside the range [20 • C; 25 • C] and RH int outside the range [30%; 70%]; (2) Threshold of CO 2 protection exceeded (1625 ppm for a mean of 8 h); (3) Threshold of TVOC protection exceeded (0.52 ppm for a mean of 8 h); (4) Threshold of CH 2 O protection exceeded (0.08 ppm for a mean of 8 h).
As for T int and RH int , this "excessive" percentage is considered to be reasonable in assessments of indoor environments, since existing regulations are relatively recent, and the buildings have envelope and HVAC systems that are mostly unprepared for the new, very high standards. Moreover, if the percentage defined is too small (e.g., <5-10%), implementing climate control in these spaces would become quite expensive.

ECC 1
In the compartments of ECC 1, in both trials, approximately constant temperatures and relative humidity were recorded; they were within the recommended values (20 • C-25 • C; 30-70%). This may be because the building in question is recent, with improved systems relative to the ECC 2. An example of this is the existence of double-glazed windows with aluminum frames, without thermal brakes, in all of the compartments, as well as the existence of thermal insulation in the envelope of the building. Table 9 shows a statistical analysis of indoor pollutants (CO 2 and TVOC), recorded in the compartments of ECC 1 during the second trial.  (2) The mean concentration of CO 2 and TVOC were calculated without taking into account any errors (e.g., external or equipment); (3) "Maximum of 8 h means" is the maximum value that occurs in sequentially-calculated 8 h means. "Maximum of 8 h means" occurs during "Maximum measurement period" (See Table 6). Approximately 5500 arithmetic means were calculated.
According to the results presented in Table 9 and shown in Figure 2, we conclude that: (1) The living room presented a maximum mean value of CO 2 which is above the protection threshold. From Figure 2, we can see that the maximum peaks of pollutants occurred during the period of the room's occupancy, mostly during the afternoon. We can also see that outside the period of occupancy, the values of CO 2 remained below the regulatory limits. The high values may therefore be due to the high density of occupancy of the living room, reduced ACH, or even to possible combustion processes, since the kitchen and the dining hall are located in the vicinity of the living room; (2) TVOC concentrations were not of concern in any of the analyzed compartments. The standard deviation values of the TVOC of the rooms were high, and we may conclude that the most influential parameters (type of activities and ACH) vary quite a bit during occupancy.  Table 9 shows a statistical analysis of indoor pollutants (CO2 and TVOC), recorded in the compartments of ECC 1 during the second trial.
According to the results presented in Table 9 and shown in Figure 2, we conclude that: (1) The living room presented a maximum mean value of CO2 which is above the protection threshold. From Figure 2, we can see that the maximum peaks of pollutants occurred during the period of the room's occupancy, mostly during the afternoon. We can also see that outside the period of occupancy, the values of CO2 remained below the regulatory limits. The high values may therefore be due to the high density of occupancy of the living room, reduced ACH, or even to possible combustion processes, since the kitchen and the dining hall are located in the vicinity of the living room; (2) TVOC concentrations were not of concern in any of the analyzed compartments. The standard deviation values of the TVOC of the rooms were high, and we may conclude that the most influential parameters (type of activities and ACH) vary quite a bit during occupancy. (2) The mean concentration of CO2 and TVOC were calculated without taking into account any errors (e.g. external or equipment); (3) "Maximum of 8 h means" is the maximum value that occurs in sequentiallycalculated 8 h means. "Maximum of 8 h means" occurs during "Maximum measurement period" (See Table 6). Approximately 5500 arithmetic means were calculated.
.   Table 10 shows a statistical analysis of the temperatures and relative humidity recorded in the compartments of ECC 2 during the first trial. We may essentially conclude that: (1) The rooms analyzed show an excessive percentage of time in which the indoor temperatures are lower than prescribed (recommended range: 20 • C to 25 • C). However, comparing these with the mean temperatures, we can state that temperatures which are uncomfortably low are only slightly lower than 20 • C; (2) The temperatures in the living rooms were found to be within the recommended guidelines. These conditions of thermal comfort may reflect better climate control and the fact that these compartments had a high occupancy density throughout the day; (3) The living rooms had reasonable mean RH values; (4) The rooms had excessive percentages of time where the RH values registered were higher than the recommended maximum limit. Table 10. Statistical analysis of the hygrothermal parameters recorded in compartments of ECC 2: 1 st trial (4 to 8 January). (2) ∆T is the difference between the means of T int and T ext ;

ECC 2-1 st Trial
(3) Perc is "Percentage of time that exceeds a certain value"; see Nomenclature.
The thermal comfort of rooms 1 and 2 and living rooms 1 and 2 of ECC 2 was assessed using the adaptive model proposed by LNEC [28], as shown in Figure 3.  The statistical analysis of the indoor pollutants (CO2 and TVOC) recorded in the compartments of ECC 2 during the first trial showed that: (1) Room 1 and living room 2 had high mean CO2 values. Nevertheless, none of the compartments analyzed presented mean TVOC values of concern; (2) With the exception of living room 1, all the compartments analyzed had a maximum mean value of CO2 which was above the protection threshold. Table 11 presents the ACH of living rooms 1 and 2 in ECC 2.
From the results presented, we may conclude that both living rooms analyzed had poor ACH (well below the regulatory ACH in both cases). Table 11. Ventilation rates of living rooms 1 and 2 in ECC 2: 1 st trial. The "Operative temperature" can be calculated, with good approximation, considering the arithmetic mean between T int and T mp (ASHRAE 55, 2004 [29]; EN ISO 7730, 2005 [30]).
Considering the use of active air conditioning (central heating with water radiators), the results revealed the existence of a thermally comfortable environment in practically all compartments, with the temperature data within the established "comfortable" guideline values.
The statistical analysis of the indoor pollutants (CO 2 and TVOC) recorded in the compartments of ECC 2 during the first trial showed that: (1) Room 1 and living room 2 had high mean CO 2 values. Nevertheless, none of the compartments analyzed presented mean TVOC values of concern; (2) With the exception of living room 1, all the compartments analyzed had a maximum mean value of CO 2 which was above the protection threshold. Table 11 presents the ACH of living rooms 1 and 2 in ECC 2. Notes: a To determine mean ACH by the CO 2 decay method, a total of 5 trials were used for living room 1 and 4 for living room 2; b Air flow rates were obtained in [19]; q RECS means "Air flow rate", obtained in accordance with "Ordinance 353-A/2013" (see Nomenclature); c ACH RECS means "Air change rate", obtained in accordance with "Ordinance 353-A/2013" (see Nomenclature).
From the results presented, we may conclude that both living rooms analyzed had poor ACH (well below the regulatory ACH in both cases). Table 12 shows the results of the pollutant measurements. With respect to the values presented, and taking the measurement period into account (≈ 5 min), we may conclude that the triple room presented elevated levels of formaldehyde. No potential source was identified; therefore, we speculate that this may be due to the wall coverings or other materials used. These values require further investigation.

1 st Trial
The hygrothermal comfort conditions are shown in Figure 4 and Table 13.
With respect to the values presented, and taking the measurement period into account (≈ 5 min), we may conclude that the triple room presented elevated levels of formaldehyde. No potential source was identified; therefore, we speculate that this may be due to the wall coverings or other materials used. These values require further investigation.
The hygrothermal comfort conditions are shown in Figure 4 and Table 13. It should be noted that in the ECC 3, the measurement in the living room was not performed simultaneously with the other two compartments, which is why this compartment is not shown in Figure 4.  Figure 4 and Table 13 leads us to conclude that: (1) A cyclical variation of the interior temperature is noticeable. This variation is due to the heating schedule, i.e., heating periods start at 6.00 a.m. and 6.00 p.m.; (2) The compartments present reasonable mean values for the mean indoor temperature, reflecting, in particular, the existing climate control/heating systems; (3) There is an excessive percentage of time with temperatures below regulations in the room (perhaps reflecting the opening of windows while cleaning); (4) There was some time in the two compartments in which the temperatures were above those prescribed by regulation. This may be due to their orientation (SE and E) or insufficient sun protection with regards to the windows, as in the living room; (5) The compartments do not present levels of RH of concern.

RH int [%]
Text It should be noted that in the ECC 3, the measurement in the living room was not performed simultaneously with the other two compartments, which is why this compartment is not shown in Figure 4.
An analysis of Figure 4 and Table 13 leads us to conclude that: (1) A cyclical variation of the interior temperature is noticeable. This variation is due to the heating schedule, i.e., heating periods start at 6.00 a.m. and 6.00 p.m.; (2) The compartments present reasonable mean values for the mean indoor temperature, reflecting, in particular, the existing climate control/heating systems; (3) There is an excessive percentage of time with temperatures below regulations in the room (perhaps reflecting the opening of windows while cleaning); (4) There was some time in the two compartments in which the temperatures were above those prescribed by regulation. This may be due to their orientation (SE and E) or insufficient sun protection with regards to the windows, as in the living room; (5) The compartments do not present levels of RH of concern.

2 nd Trial
The 2 nd trial took place in the spring of 2015, continuously recording concentrations of CO 2 and TVOC only at one point, with a 2-min time interval and a "Maximum measurement period" between 1 and 8 days. Table 14 shows the results of the measurements of pollutants and ACH. Notes: (1) The measurements in the living room refer to the usual period of occupancy: 6.30 a.m. to 6.30 p.m.; (2) A total of 8 trials were conducted in the living room, and 5 in the triple room, to determine the mean ACH by the CO2 decay method. Figures 5 and 6 show the temporal evolution of CO2 and TVOC. The initial points of the CO2 decay method are shown; they were used to determine the ACH through the decay technique. Points with maximum levels of TVOC are also shown.  From Table 14 and Figures 5 and 6, we may conclude that: (1) The living room presents very low values of ACH; (2) In the triple room, the peaks of CO2 and TVOC occurred predominantly between 10:00 and 11:00 a.m., followed by a marked decay of CO2. This conjugation of behavior may be the result of cleaning actions, followed by opening windows.

Conclusions and Recommendations
From the results obtained in both ECC in Viseu, the following conclusions may be drawn: (1) With the exception of the concentration of CO2 in the living room, ECC 1 has an IEQ which is within the regulatory threshold values and standards; (2) In ECC 2, the rooms have high percentages of time with temperatures below regulation standards, and reveal worrying RH values (with excessive percentages of time with RH values above the recommended maximum limit); (3) In ECC 2, the rooms have excessive periods with temperatures below regulation, and reveal RH values that raise some concerns (with excessive periods of time with RH values above the recommended maximum limit); (4) With the exception of living room 1, all rooms in ECC 2 had maximum mean values of CO2 which were above the protection threshold; (5) In assessing the thermal comfort by applying the adaptive comfort model proposed by LNEC and regarding ECC 2, the rooms are comfortable overall; (6) The ACH were found to be insufficient, with values generally below the required levels for all of the analyzed compartments .
From the results obtained in the ECC in Covilhã, the following conclusions stand out: (1) The RH values in the compartments do not raise concern; (2) The triple room has an excessive percentage of time with below regulation temperatures (perhaps due to opening windows during cleaning From Table 14 and Figures 5 and 6, we may conclude that: (1) The living room presents very low values of ACH; (2) In the triple room, the peaks of CO 2 and TVOC occurred predominantly between 10:00 and 11:00 a.m., followed by a marked decay of CO 2 . This conjugation of behavior may be the result of cleaning actions, followed by opening windows.

Conclusions and Recommendations
From the results obtained in both ECC in Viseu, the following conclusions may be drawn: (1) With the exception of the concentration of CO 2 in the living room, ECC 1 has an IEQ which is within the regulatory threshold values and standards; (2) In ECC 2, the rooms have high percentages of time with temperatures below regulation standards, and reveal worrying RH values (with excessive percentages of time with RH values above the recommended maximum limit); (3) In ECC 2, the rooms have excessive periods with temperatures below regulation, and reveal RH values that raise some concerns (with excessive periods of time with RH values above the recommended maximum limit); (4) With the exception of living room 1, all rooms in ECC 2 had maximum mean values of CO 2 which were above the protection threshold; (5) In assessing the thermal comfort by applying the adaptive comfort model proposed by LNEC and regarding ECC 2, the rooms are comfortable overall; (6) The ACH were found to be insufficient, with values generally below the required levels for all of the analyzed compartments.
From the results obtained in the ECC in Covilhã, the following conclusions stand out: (1) The RH values in the compartments do not raise concern; (2) The triple room has an excessive percentage of time with below regulation temperatures (perhaps due to opening windows during cleaning actions); (3) The living room has very low ACH values; (4) The triple room has high levels of formaldehyde.
The previous conclusions imply the need for action concerning the heating, maintenance, and ventilation conditions, so that the spaces operate within the appropriate conditions of comfort and air quality.

Conflicts of Interest:
The authors declare no conflict of interest.