Expe imen al assessmen o he in e ac ion be ween indoo ai
quali y and he mal com o in na u ally en ila ed seconda y
class ooms in sou he n Spain
R. Escand´
on
a,*
, C.M. Calama-Gonz´
alez
b
, R. Su´
a ez
a
a
Ins i u o Uni e si a io de A qui ec u a y Ciencias de la Cons ucci´
on, Escuela T´
ecnica Supe io de A qui ec u a, Uni e sidad de Se illa, A . de Reina
Me cedes 2, 41012, Se illa, Spain
b
Depa men o A chi ec u al Cons uc ions and Con ol, Escuela T´
ecnica Supe io de Edi icaci´
on, Uni e sidad Poli ´
ecnica de Mad id, A da. Juan de
He e a 6, 28040, Mad id, Spain
HIGHLIGHTS
•Simul aneous assessmen o indoo ai quali y and he mal com o .
•Long- e m moni o ing o main indoo en i onmen al and pollu an a iables.
•An excess o hou s o o e - en ila ion is de ec ed, especially in summe .
•Indoo ai quali y is gene ally achie ed bu o he de imen o com o condi ions.
•O e hea ing and a mode a e loss o cogni i e pe o mance a e ound in summe .
ARTICLE INFO
Keywo ds:
Medi e anean clima e
Ven ila ion a e
Indoo ai quali y
The mal com o
Field measu emen s
Cogni i e pe o mance
ABSTRACT
Cu en Eu opean policies ocus on achie ing clima e neu ali y by 2050. Howe e , he COVID-19
c isis has dis up ed social condi ions, eigni ing he deba e on buildings wi h high occupancy and
s a ic use s o long pe iods, such as schools, gi en hei inadequa e heal h and com o condi-
ions. In he Medi e anean clima e, mos school buildings lack sui able en ila ion sys ems, due
o ei he hei age o a eluc ance o use mechanical en ila ion sys ems.
This s udy p o ides a quan i a i e analysis o cu en beha iou al and en i onmen al ac o s
a ec ing pollu an exposu e, co e ing he gap in he exis ing li e a u e on simul aneous assess-
men on indoo ai quali y condi ions (CO
2
, PM
2.5
, PM
10
), and hyg o he mal com o ( empe a-
u e and ela i e humidi y) in a pos -COVID scena io in exis ing seconda y school buildings in
sou he n Spain. Fo his pu pose, a con inuous moni o ing o indoo en i onmen al condi ions in
cooling, mild, and hea ing seasons is p oposed o assess he in luence o na u al en ila ion
condi ions on indoo ai quali y and he mal com o , ins ead o he sho - e m moni o ing
ocused on speci ic pe iods equen ly ound in p e ious s udies. The esul s show a widesp ead
use o na u al o e en ila ion h ough windows, especially in summe (mo e han 50 % o he
occupied hou s), o gua an ee indoo ai quali y condi ions (wi h CO
2
below 900 ppm du ing
almos 100 % o he occupied hou s). Howe e , in gene al, his in ol es clea ly comp omising
he mal condi ions (wi h seasonal a e age alues abo e 25 ◦C and 100 % o he occupied hou s in
discom o du ing he ho es weeks) and a mode a e loss o cogni i e pe o mance du ing mo e
han 97 % o he summe occupied hou s.
* Co esponding au ho .
E-mail add ess: [email p o ec ed] (R. Escand´
on).
Con en s lis s a ailable a ScienceDi ec
Case S udies in The mal Enginee ing
jou nal homepage: www.else ie .com/loca e/csi e
h ps://doi.o g/10.1016/j.csi e.2025.106335
Recei ed 24 Janua y 2025; Recei ed in e ised o m 7 May 2025; Accep ed 13 May 2025
Case S udies in The mal Enginee ing 72 (2025) 106335
A ailable online 14 May 2025
2214-157X/© 2025 The Au ho s. Published by Else ie L d. This is an open access a icle unde he CC BY-NC-ND license
( h p://c ea i ecommons.o g/licenses/by-nc-nd/4.0/ ).
1. In oduc ion
In addi ion o complying wi h cu en egula o y equi emen s, he ene gy upg ading needed o school building s ock is also acing
wo new challenges in he con ex o Medi e anean clima e and way o li e. The i s o hese is social and is linked o indoo ai quali y
and occupan s’ heal h, e idenced du ing he COVID-19 pandemic gi en he sp ead o in ec ious pa icles in high-occupancy indoo
en i onmen s [1], while he second challenge is en i onmen al, wi h a emp s being made o achie e clima e neu ali y o ace p o en
clima e change [2]. Nume ous s udies in schools examine he co ela ion o di e se indoo en i onmen al indica o s wi h heal h
p oblems [3] (such as in luenza o he COVID-19 pandemic), sugges ing ha , in many cases, he usual na u al en ila ion sys ems in
class ooms in he Medi e anean a ea [4] a e insu icien o educe he isk o pa hogen ansmission [5] and a e indi ec ly impac ing
he s uden s’ lea ning capaci y [6].
The Wo ld Heal h O ganiza ion (WHO) does no classi y CO
2
as a pollu an , bu i s concen a ion a e is gene ally used as he main
indica o o indoo ai quali y (IAQ) in schools [7]. Howe e , minimizing CO
2
concen a ions is no su icien o main ain adequa e
IAQ condi ions [8], and no all he concen a ion le els o di e en pollu an s a e simul aneously educed by inc easing he na u al
en ila ion a e. The e ec s o changes in he low a e and en ila ion pe iods di e be ween pollu an s [9]. While longe na u al
en ila ion pe iods a ou CO
2
dissipa ion, hey can also lead o an inc ease in pa icula e ma e (PM) when he ou doo in ake ai
(ODA) is o poo quali y [10]. The e o e, al hough heal h isks in schools a e mainly assessed in ela ion o exposu e o high con-
cen a ions o CO
2
[11], o he pollu an s such as PM [12], and he he mal condi ions o he space [13], should be con olled.
In addi ion o p o iding spaces o lea ning, he class oom layou should a ou heal h and social condi ions [14], bene i ing global
Indoo En i onmen al Quali y (IEQ) [15]. Any ac i i y associa ed wi h b ea hing o ms espi a o y pa icles ha emain in he ai
[16], so ha achie ing an adequa e en ila ion a e is a p io i y. Inc easing he en ila ion a e, besides dec easing CO
2
concen a ion,
educes he sp ead o disease [17], imp o es academic pe o mance [18], and aids cogni i e enhancemen [19].
The e o e, en ila ion measu es mus be adop ed in class ooms o ensu e bo h a heal hy en i onmen and app op ia e hyg o-
he mal beha iou . Bu he limi s o CO
2
concen a ion conside ed accep able in schools a e a iable: 2000 ppm by he Commi ee o
Indoo Guidelines Value o he Ge man Fede al En i onmen Agency [20]; 1000 ppm ecommended by ASHRAE S anda d 62.1 [21]
( a e o 7 l/s pe pe son); o he alues below 600 ppm se in EN 16798–1 [22] o a ca ego y IDA 2 (12.5 l/s pe pe son). Fu he mo e,
no s anda d p oposes a combined IAQ and he mal com o app oach [23].
In he Medi e anean a ea, unde an e oneous conside a ion o being a ‘benign clima e’, du ing he p e-pandemic pe iod class-
ooms we e o en na u ally en ila ed, elying on he pe sonal pe cep ion o s uden s and eache s. This esul ed in unknown and
uncon olled en ila ion a es, in many cases below s anda ds, as well as a e age CO
2
concen a ions abo e he ecommended limi s.
Unde hese condi ions he e was equen ly no adequa e co ela ion wi h hyg o he mal com o condi ions [24] o a la ge pa o he
school pe iod, due o a se ies o ac o s, including he in luence o seasonal changes [25]. In he win e pe iod he e was widesp ead
inadequa e ai quali y, wi h indoo empe a u es condi ioned by he en ila ion a e and he use o hea ing sys ems. He acleous and
Michael [26] analysed he impac o na u al en ila ion on bo h he mal com o and ai quali y, es ablishing a co ela ion wi h CO
2
le els in 114 seconda y school buildings in Cyp us. A e age concen a ions o 1604 ppm, highe han he no ma i e alues, and
a e age indoo empe a u es o 19.3 ◦C, we e ob ained.
In sp ing, a ou able ou doo condi ions o en ensu e indoo empe a u es in com o able anges, al hough CO
2
concen a ions
emain high. In G eece, Do izas e al. [27] e alua ed en ila ion a es and indoo ai pollu an s in 9 na u ally en ila ed schools. A
posi i e co ela ion was also ound o CO
2
concen a ions, wi h a e age alues o 1482 ppm, and he numbe o s uden s. PM con-
cen a ions we e signi ican ly a ec ed by en ila ion a es, he p esence o s uden s and indoo pollu ion sou ces. In sou he n Spain,
Gil-B´
aez e al. [28] moni o ed 9 schools in sp ing, obse ing indoo empe a u es o 20–25 ◦C bu a e age daily CO
2
concen a ion o
abou 1500 ppm. In summe , high ou doo empe a u es condi ion he en ila ion o class ooms. San amou is e al. [29] analysed CO
2
concen a ions in 27 schools in A hens, whe e he en ila ion low a e was below 8 l/s and he a e age concen a ion was 1400 ppm.
Fo ou doo empe a u es o be ween 20 and 28 ◦C, he e was a endency o limi he opening o windows and educe he low a e,
p o ec ing he occupan s o he class ooms om he ambien hea .
These widesp ead poo condi ions in class ooms lead di e en au ho s o es ablish ecommended CO
2
concen a ions o p omo e
heal hy en ila ion condi ions. Howe e , hey ail o add ess how hese in luence he mal condi ions. In sou he n Spain, K awczyk
e al. [30] p opose a a e o 2.5–5 ACH o ensu e IDA 2 ca ego y le els and CO
2
concen a ions below 1000 ppm, which can esul in
6–9 ACH a maximum occupancy. Acco ding o SINPHONIE guidelines [31] CO
2
concen a ions should no exceed 1500 ppm.
Du ing he COVID-19 pandemic, and ollowing signi ican IAQ p oblems in class ooms, schools we e highligh ed as a sensi i e a ea
o possible con agion and special heal h ca e [32]. As a esul , s anda d en ila ion a es we e conside ed insu icien , and o e -
en ila ion a a es o 5–6 ACH was ecommended in he Ven ila ion Guide o Ha a d [33], ega dless o any possible ad e se wea he
condi ions. The p io i y in class ooms was o ensu e heal h a he han com o . Ven ila ion was he e o e conside ed as a p e en i e
measu e o educe he isk o i us ansmission [34], mainly using na u al en ila ion h ough windows, wi h clea bene icial e ec s
on indoo ai quali y [35], al hough no on he mal com o , which depended on ou doo wea he condi ions.
Pa icula ly in win e , in 13 examina ion class ooms in Ex emadu a (Spain), Mi anda e al. [36] eco ded a e age CO
2
concen-
a ion le els be ween 450 and 670 ppm. These adequa e en ila ion condi ions a ec ed he he mal com o o he occupan s, wi h a
dissa is ac ion a e o be ween 25 and 72 % when ou doo empe a u es d opped below 6 ◦C. Alonso e al. [37] moni o ed wo
p e-school class ooms loca ed in Se illa (Spain), wi h windows open and hea ing on du ing all eaching hou s. CO
2
concen a ions
we e below 1000 ppm, and he a e age indoo empe a u e was 15 ◦C, ep esen ing a wo sening o com o condi ions compa ed o he
p e-pandemic pe iod. In au umn, wi h mode a e ou doo empe a u es, Villanue a e al. [38] e alua ed en ila ion condi ions (CO
2
)
R. Escand´
on e al.
Case S udies in The mal Enginee ing 72 (2025) 106335
2
and suspended pa icula e ma e (PM
2.5
, PM
10
) le els in seconda y school class ooms loca ed in Ciudad Real (Spain). CO
2
concen-
a ions we e in he ange o 800–1000 ppm, while indoo empe a u e was be ween 21.6 and 26.7 ◦C. Aguila e al. [39] moni o ed a
class oom in G anada (Spain) du ing a summe and win e pe iod wi h na u al en ila ion. The esul s shown low CO
2
le els, bu
indoo empe a u e was a ec ed in di e en en ila ion s a egies, wi h esul s close o ou doo condi ions.
A e he COVID-19 pandemic, and he e u n o no mali y in class ooms, he e ec i eness o en ila ion sys ems should be
econside ed in o de o gua an ee a en ila ion a e bu also adequa e condi ions o he mal com o and ene gy e iciency [40].
Howe e , cu en ly, ew s udies p o ide a combined analysis o ai quali y and he mal com o condi ions in na u ally en ila ed
Medi e anean class ooms. O pa icula no e is he s udy by Miao e al. [41] moni o ing 16 schools in Ca alu˜
na (Spain). The esul s
showed ha poo indoo ai quali y was mainly due o closing windows and doo s in win e , while he mal discom o occu ed in
summe due o high indoo empe a u e. The indings sugges ha a p ope en ila ion p o ocol is he key o balancing indoo ai
quali y and he mal com o . Rome o e al. [42], a e he moni o ing o uni e si y classes in Ex emadu a (sou he n Spain) a he end
o June, de ec ed a e age CO
2
concen a ions a ound 550 ppm wi h indoo empe a u es be ween 22 and 27 ◦C. Simila ly, To iani
e al. [43] explo ed he ela ionship be ween he mal com o and IAQ in 26 class ooms in Pisa (I aly). The s udy shows ha occupan s’
pe cep ion o IAQ is in e sely p opo ional o ope a ing empe a u e and CO
2
concen a ion.
In summa y, he e iew o he li e a u e on IEQ in buildings shows ha :
- Al hough he e is a weal h o s udies on indoo ai quali y and he mal com o in he Medi e anean a ea, he e is a gap in he
li e a u e when looking o s udies ha analyse bo h aspec s in a combined way, especially in pos -co id imes.
- Recommended en ila ion a es may no gua an ee ai quali y and he mal com o , bu no s anda d p oposes a combined app oach
o IAQ and he mal com o , which would allow o mo e in o med ade-o decisions conside ing IAQ, he mal com o , and
ene gy a ge s.
- Mos s udies a e based on measu emen s in speci ic pe iods, and no on a con inuous yea ly basis.
The associa ion be ween IAQ and he mal com o is clea , as he ou doo ai in oduced in o he class oom a ec s he indoo
he mal condi ions [44]. The e o e, he no el y and ele ance o his s udy lies in illing he gap de ec ed in he exis ing li e a u e,
add essing he ollowing ques ions in class ooms in a Medi e anean clima e:
- Wha s a egies a e con empla ed o ensu e indoo en i onmen al quali y and main ain a low isk o con agion a e he pandemic
pe iod?
- A e he usual solu ions o na u al en ila ion h ough windows adequa e o simul aneously gua an ee IAQ and com o ?
- Wha a e he causes o hei cu en en i onmen al beha iou in he di e en seasons?
Acco dingly, he main objec i e o his wo k is he quan i a i e diagnosis and comp ehensi e assessmen o cu en beha iou al
and en i onmen al ac o s ela ing o exposu e o pollu an s, IAQ, and he mal com o condi ions in ep esen a i e exis ing seconda y
school buildings in he Medi e anean clima e. This is ca ied ou by long- e m moni o ing o he main indoo en i onmen al a iables
( empe a u e and ela i e humidi y) and high-p io i y pollu an s (CO
2
, PM
2.5
and PM
10
). In addi ion, pos -COVID na u al en ila ion
s a egies a e analysed, assessing hei in luence on IAQ, he mal com o , and cogni i e pe o mance o s uden s.
Fig. 1. Me hodology lowcha .
R. Escand´
on e al.
Case S udies in The mal Enginee ing 72 (2025) 106335
3
The pape is s uc u ed as ollows: Sec ion 2p esen s he case s udies, ma e ials and me hods ollowed o ca y ou he moni o ing
campaigns and esul s assessmen ; Sec ion 3 epo s he esul s and discussion o he global s a is ical analysis o he h ee main
seasons, he speci ic e alua ion o he ho es and coldes weeks, he en ila ion a es and cogni i e pe o mance loss assessmen ; and
Sec ion 4p o ides o he conclusions o he wo k and u u e esea ch s eps.
2. Me hodology
This wo k is de eloped wi hin he esea ch p ojec “Re o i en ila ion s a egies o heal hy and com o able schools wi hin a
nea ly ze o-ene gy building ho izon” (COHEVES). The i s phase o his p ojec ocused on he ca aloguing and documen a ion o
seconda y schools in sou he n Spain in o de o selec ep esen a i e case s udies [45]. Based on his, in si u measu emen campaigns
we e ca ied ou in h ee seconda y schools ( wo class ooms pe school), loca ed in ep esen a i e clima ic zones o sou he n Spain,
du ing a comple e school yea . A e being il e ed and ea ed, he measu ed da a ha e been used o cha ac e ize he en i onmen al
beha iou o hese seconda y schools, e alua ing hyg o he mal com o condi ions and indoo ai quali y du ing occupied and un-
occupied pe iods. Fig. 1 shows a g aphic summa y o he me hodology used in his wo k.
2.1. Selec ed case s udies
In o de o ca y ou he moni o ing campaigns, h ee case s udies we e selec ed om he mos common building ypology in
seconda y schools in sou he n Spain: he class - co ido - class s uc u e. In each o hese schools, wo class ooms wi h opposing
o ien a ions and loca ed on in e media e loo s we e measu ed. Fig. 2 shows he in e io iew o a ypical class oom in each o he
schools ( açade and in e io pa i ion wi h co ido ).
Table 1 summa izes he main cha ac e is ics o he 6 case s udy class ooms. As can be seen, he h ee schools a e loca ed in di e en
Medi e anean clima ic zones conside ed ep esen a i e o he clima e o sou he n Spain. This clima ic classi ica ion is aken om he
Spanish Technical Building Code (CTE [46]), which de ines win e clima e se e i y wi h le e s om ‘A’ o ‘E’ (mild o cold) and
summe clima e se e i y wi h numbe s om 1 o 4 (mild o ho ). Thus, he s udy sample co e s he 3 mos ep esen a i e win e zones
in sou he n Spain (A, B, and C, in inc easing o de o se e i y), and he 2 mos epea ed summe zones (3 and 4, in inc easing o de o
se e i y). Fu he mo e, he case s udies selec ed co e he wo main pe iods o cons uc ion o seconda y school s ocks: be o e 1979,
when he i s Spanish egula ion on he mal condi ions in buildings (NBE CT 79 [47]) came in o o ce; and be ween 1979 and 2006,
Fig. 2. In e io iew o he case s udies: (a) S1 – M´
alaga; (b) S2 – Se illa; (c) S3 – Puen e Genil.
R. Escand´
on e al.
Case S udies in The mal Enginee ing 72 (2025) 106335
4
when he cu en Spanish Technical Building Code [46] was implemen ed.
The class ooms in cases 1 and 3 ha e a simila olume and occupancy, while hose in case 2 a e somewha smalle bu wi h lowe
occupancy, gi ing a e y simila a io o numbe o people pe olume in all h ee cases. This is in keeping wi h he es o he sec-
onda y school s ock in sou he n Spain. The s uden s occupying he case s udy class ooms a e aged be ween 15 and 19. Table 1 also
compiles o he a iables wi h a g ea in luence on he en ila ion and en i onmen al beha iou o he class ooms, such as he numbe
o doo s (which a ou c oss en ila ion in his ypology), window su ace, sola p o ec ion, and HVAC sys ems. All class ooms a e
na u ally en ila ed by use s manually opening windows, and ha e adia o s o hea ing and ans o ci cula e he ai in summe (excep
case 1), bu no ac i e cooling sys ems. Class ooms a e gene ally used om 8:30 o 15:00 h, wi h a b eak be ween 11:30 and 12:00 h
(when he class oom is emp y).
2.2. In-si u measu emen campaigns
In his wo k, long- e m in-si u measu emen campaigns we e ca ied ou con inuously o e a whole school yea in he case s udy
class ooms. The main hyg o he mal pa ame e s ( empe a u e and ela i e humidi y) and ai quali y pa ame e s (CO
2
, PM
2.5
and PM
10
)
we e measu ed using mul i unc ion senso s (Fig. 3). Sensone Mul isenso SW20 da alogge s, whose main cha ac e is ics a e desc ibed
in Table 2, we e used. In addi ion o ai empe a u e, hese senso s measu e globe empe a u e, al hough he globe senso has ailed in
some class ooms. The e o e, a compa ison o ai and globe empe a u e measu emen s eco ded in di e en class ooms h oughou he
yea was ca ied ou , showing minimal di e ences, and p omp ing he decision o use he ai empe a u e measu emen s (wi hou da a
losses) o analysis. The unce ain ies associa ed wi h he measu ing equipmen a e wi hin accep able pa ame e s acco ding o EN ISO
7726 [48] and EN ISO 16000–26 [49].
Once calib a ed, he senso s we e placed in he class ooms, in he cen e o he in e io pa i ion wi h he co ido ( o a oid
d augh s and di ec sola adia ion), and a a heigh o 1.8 m o a oid in e e ing wi h class oom ope a ion (Fig. 3). Table 3 p esen s he
comple e measu emen pe iods o indi idual cases, and he weeks wi h maximum and minimum indoo empe a u es ha e also been
highligh ed, since hey will be analysed in de ail a a la e s age.
Fo he subsequen analysis o he measu ed da a, limi o e e ence alues ha e been es ablished o he di e en pa ame e s
(Table 4). These h esholds e e o cu en egula ions o guidelines in o ce in Spain. Fo example, he h eshold se o CO
2
le el
ollows he design condi ions es ablished by he Regula ion on The mal Ins alla ions in Buildings (RITE [50]), which in u n is go -
e ned by EN 16798–3:2017 [51]. This egula ion es ablishes ou ai quali y ca ego ies: IDA 1, op imum ai quali y; IDA 2, good ai
quali y; IDA 3, medium ai quali y; and IDA 4, poo ai quali y. In class ooms, IDA 2 ai quali y is equi ed, whe e a CO
2
concen a ion
Table 1
Main cha ac e is ics o he case s udies.
Case Loca ion
(clima e zone)
Pe iod o
cons uc ion
O ien a ion
(case)
Volume
[m
3
]
Max.
occupa ion
N .
Doo s
Window Su ace
(p ac icable) [m
2
]
Sola
p o ec ion
HVAC
sys em
S1 M´
alaga (A3) 1979–2006 No h (S1.N) 164.70 31 2 10.2 (5.1) Ve ical
sla s
Radia o s
Sou h (S1.S) 164.70 31 2 10.2 (5.1) Ve ical
sla s
Radia o s
S2 Se illa (B4) <1979 No h (S2.N) 130.98 24 1 7.3 (3.6) Rolle
blinds
Radia o s
Fans
a
Sou h (S2.S) 130.98 24 1 7.3 (3.6) Rolle
blinds
Radia o s
Fans
a
S3 Puen e Genil
(C4)
<1979 Eas (S3.E) 156.6 31 2 8.2 (4.1) Rolle
blinds
Radia o s
Fans
Wes (S3.W) 156.6 31 2 8.2 (4.1) Rolle
blinds
Radia o s
Fans
a
Ai -condi ioning is exis ing, bu ou o se ice.
Fig. 3. Senso s used o moni o ing.
R. Escand´
on e al.
Case S udies in The mal Enginee ing 72 (2025) 106335
5
o less han 500 ppm abo e he ou doo ai concen a ion (es ima ed a 400 ppm) mus be main ained.
As he Spanish egula ions do no de ine he daily limi s o PM
2.5
and PM
10
, he indica ions p o ided by he WHO in i s Global ai
quali y guidelines [52] ha e been ollowed. The hyg o he mal com o band o non- esiden ial buildings es ablished in RITE is used as
e e ence in his wo k (Table 4). E en hough he he mal condi ions o educa ional buildings a e no usually s able, due o changes in
occupancy du ing each session, p e ious s udies suppo he use o s a ic com o assessmen models, since i akes e y li le ime o
s uden s o each a s able he mal s a e [53].
2.3. Resul s assessmen
Once in-si u measu emen da a a e collec ed and p ocessed, a ull quan i ied assessmen o he en i onmen al beha iou o he case
s udies can be ca ied ou , ocusing p ima ily on indoo ai quali y and com o . Fo his pu pose, a s a is ical analysis o he compiled
da a was conduc ed, including a compa ison wi h he limi o e e ence alues se ou in Table 4. Fu he mo e, en ila ion a es we e
es ima ed using he me hodology de ailed in sec ion 2.3.1 in o de o u he analyse he in luence o na u al en ila ion s a egies on
IAQ and com o condi ions. Finally, cogni i e pe o mance loss was calcula ed acco ding o he me hodology desc ibed in sec ion
2.3.2 o assess he in luence o he mal condi ions on s uden s’ academic pe o mance.
2.3.1. Ai change a es es ima ion
The ‘s eady s a e’ me hod desc ibed in Re . [54] was applied o es ima e he app oxima e na u al en ila ion o ai exchange a e
h ough he opening o windows in he class ooms unde s udy. This me hod can be used when he CO
2
le el has eached a s a iona y
concen a ion. In his wo k, wo alues we e calcula ed o each day (one du ing he i s pa o he mo ning, be o e he b eak, and one
du ing he second pa ), whe e a s able CO
2
le el was de e mined when occupancy condi ions emained ixed o a leas h ee
comple e ai changes. In o de o calcula e he ai change a e (As), Equa ion (1) was applied.
As [ACH] = 6×104×n×Gp
V× (Ci −Co)(1)
whe e n is he numbe o occupan s, Gp he a e age CO
2
gene a ion a e pe pe son (l/min) acco ding o Ba e man [55], V he olume
Table 2
Main cha ac e is ics o he senso s used o moni o ing.
Senso ID Ins alla ion Va iables Accu acy Range
SENSONET Indoo CO
2
(ppm) ±10 % 0 … 5000 ppm
PM
2.5
(
μ
g/m
3
)±15
μ
g/m
3
<100
±15 % >100
0–1000
μ
g/m
3
PM
10
(
μ
g/m
3
)±15
μ
g/m
3
<100
±15 % >100
0–1000
μ
g/m
3
Ai empe a u e (◦C) ±0.5 ◦C−20 … +65 ◦C
Rela i e Humidi y (%) ±3 % 0–100 %
Table 3
Moni o ing pe iods.
Case Measu emen pe iod Ho es week Coldes week
S1.N 15/09/22–08/06/23 19/09/22–25/09/22 30/01/23–05/02/23
S1.S 15/09/22 - 22/06/23 19/09/22–25/09/22 30/01/23–05/02/23
S2.N 03/10/22–16/06/23 08/05/23–14/05/23 09/01/23–15/01/23
S2.S 03/10/22–16/06/23 08/05/23–14/05/23 09/01/23–15/01/23
S3.E 15/09/22 - 22/06/23 19/09/22–25/09/22 23/01/23–29/01/23
S3.W 15/09/22–29/05/23 19/09/22–25/09/22 09/01/23–15/01/23
Table 4
Re e ence alues o each pa ame e .
Indoo Va iable Uni Recommended limi o maximum alues Regula ion/Di ec i e
CO
2
Ppm 900 ppm RITE (2021) [50]
PM
2.5
μ
g/m
3
25
μ
g/m
3
(daily) WHO (2021) [52]
PM
10
μ
g/m
3
45
μ
g/m
3
(daily) WHO (2021) [52]
Tempe a u e ◦C 23 … 25 ◦C (summe ) RITE (2021) [50]
21 … 23 ◦C (win e )
Rela i e humidi y % 45 … 60 % (summe ) RITE (2021) [50]
40 … 50 % (win e )
R. Escand´
on e al.
Case S udies in The mal Enginee ing 72 (2025) 106335
6
o he class oom (m
3
), Ci he s eady-s a e indoo CO
2
concen a ion (ppm), and Co he ou doo CO
2
concen a ion (ppm).
2.3.2. Cogni i e pe o mance loss
In o de o e alua e and quan i y he impac o he lack o com o on he cogni i e pe o mance o s uden s in he schools selec ed
as case s udies, he me hodology de ined by Wa gocki e al. [56] was applied o he da a measu ed in his s udy. The au ho s used a
me a-analysis o 18 p e ious s udies o es ablish a ma hema ical ela ionship be ween class oom empe a u e and s uden pe o mance
(Equa ion (2)), aiming o p edic he e ec s o empe a u e change on he speed o lea ning and de elopmen o school asks. This
ela ionship is only alid o empe a e clima es, applicable in an indoo empe a u e ange om 20 o 30 ◦C.
RP =0.2269 × 2−13.441 × +277.84 (2)
whe e RP is he cogni i e pe o mance and he indoo empe a u e.
To analyse he esul s ob ained, he pe cen age o cogni i e pe o mance loss (CPL ) was calcula ed acco ding o he equa ion
es ablished by Dong e al. [57] (Equa ion (3)).
CPL [%] = 100 −RP (3)
3. Resul s and discussion
3.1. Global s a is ical analysis
The i s s ep consis ed in he s a is ical analysis o he indoo a iables measu ed du ing he occupied hou s o he 2022–2023
academic yea , o ganized in o h ee pe iods: cooling (Table 5), mild (Table 6), and hea ing seasons (Table 7). In hese ables, alues
wi hin he es ablished limi s (shown in Table 4) a e ma ked in g een, while hose ou side he limi s appea in ed. This is in ended o
p o ide an o e iew o he annual beha iou o he h ee moni o ed schools.
Table 5
S a is ical analysis o indoo a iables. Cooling season (occupied hou s, 2022–2023).
Case Va iable
CO
2
[ppm]
PM
2.5
[µg/m
3
]
PM
10
[µg/m
3
]
Tempe a u e
[ºC]
Rela i e humidi y
[%]
S1.N
Minimum
400
2.00
2.00
20.80
28.00
A e age
590
13.60
14.85
25.29
47.08
Median
577
14.00
15.00
25.20
48.00
Maximum
1775
27.00
34.00
28.20
74.00
S anda d de ia ion
120
3.15
3.48
1.00
6.91
S1.S
Minimum
400
11.00
12.00
23.00
28.00
A e age
610
17.50
18.94
25.95
46.67
Median
589
17.00
18.00
25.90
48.00
Maximum
1257
32.00
36.00
28.50
62.00
S anda d de ia ion
128
3.01
3.57
1.06
6.92
S2.N
Minimum
400
10.00
10.00
23.30
18.00
A e age
599
15.84
17.22
27.10
36.96
Median
538
15.00
16.00
27.10
37.00
Maximum
1567
40.00
48.00
31.50
57.00
S anda d de ia ion
166
2.95
3.35
1.64
8.10
S2.S
Minimum
400
8.00
8.00
23.50
18.00
A e age
673
14.37
15.80
27.80
36.94
Median
594
14.00
15.00
27.80
38.00
Maximum
2579
96.00
163.00
31.70
58.00
S anda d de ia ion
257
3.80
4.39
1.51
8.06
S3.E
Minimum
400
0.00
0.00
20.50
16.00
A e age
672
4.09
4.25
26.57
37.77
Median
583
3.00
3.00
26.60
38.50
Maximum
3002
69.00
132.00
30.00
72.00
S anda d de ia ion
281
4.02
4.58
1.33
7.64
S3.W
Minimum
400
0.00
4.00
22.10
26.00
A e age
654
16.04
17.43
26.39
40.63
Median
609
16.00
17.00
26.30
41.00
Maximum
1921
38.00
42.00
29.60
63.00
S anda d de ia ion
193
3.29
3.69
1.27
6.71
* Values wi hin he es ablished limi s (shown in Table 4) a e ma ked in g een, and hose ou side he limi s
a e ma ked in ed.
R. Escand´
on e al.
Case S udies in The mal Enginee ing 72 (2025) 106335
7
In he summe pe iod (Table 5), i can be obse ed ha in case S1 (loca ed in M´
alaga) he indoo ai empe a u es in he no h-
acing class oom a e be ween 21 and 28 ◦C and in he sou h- acing class oom be ween 23 and 28.5 ◦C. In bo h cases he e is a
s anda d de ia ion o only 1 ◦C. In case S2 (loca ed in Se illa, he mos se e e clima ic zone in summe ), he minimum empe a u es
a e simila , bu he maximum empe a u es ise abo e 32 ◦C in bo h he no h- acing and sou h- acing class ooms. In his case he
s anda d de ia ion emains a a ound 1.5 ◦C. In case S3 (loca ed in Puen e Genil), he minimum indoo ai empe a u e alues a e
simila o case S1, and al hough he maximum empe a u es a e sligh ly highe (30 ◦C in he eas - acing class oom and 29.6 ◦C in he
wes - acing class oom) hey emain below hose o case S2. The s anda d de ia ions a e simila o hose calcula ed in cases S1 and S2.
Rega ding ela i e humidi y, in ascending o de , mean alues o 37 % we e measu ed in bo h class ooms in case S2 (wi h s anda d
de ia ions o 8 %), 38–40 % in case S3 (wi h s anda d de ia ions o abou 7 %), and 47 % in case S1 (wi h s anda d de ia ions o 7 %).
Fo he pa ame e s ela ing o IAQ, he a e age CO2 le els de ec ed we e be ween 600 ppm (cases S1.N, S1.S, and S2.N) and 670
ppm (S2.S and S3.E), alues signi ican ly below he maximum es ablished in cu en egula ions. The maximum alues eached we e
be ween 1300 ppm (case S1.S) and 3000 ppm (measu ed a some poin in ime in S3.E). The a e age measu ed alues o PM2.5 a y
be ween 4
μ
g/m3 (case S3.E) and 17
μ
g/m3 (S1.S), and simila a e age alues ha e been measu ed o PM10 (4–19
μ
g/m3). The
condi ions measu ed indica e good a e age ai quali y.
In he mild pe iods (Table 6), indoo ai empe a u es become equal in he di e en case s udies, wi h mean alues o 22–23 ◦C and
s anda d de ia ions o a ound 1.5 ◦C in all cases. This is also he case o ela i e humidi y, wi h mean alues o 41–43 % and s anda d
de ia ions o 8–10 % in all cases. The a e age CO
2
le els inc ease sligh ly wi h espec o he summe pe iod, wi h alues be ween 670
ppm (S1.N) and 920 ppm (S2.S), a alue ha al eady eaches he es ablished no ma i e limi s. In his class oom, occasional maximum
alues o almos 4800 ppm a e eco ded, indica ing ha en ila ion in mid-seasons is no as in ensi e in all he class ooms measu ed.
This inc ease is no obse ed in he a e age alues measu ed o PM
2.5
, which in his pe iod a e be ween 4.5
μ
g/m
3
(case S3.E) and
16.6
μ
g/m
3
(S2.N), no in hose o PM
10
(4.8–18
μ
g/m
3
).
Du ing win e (Table 7), in case 1, he indoo ai empe a u es in he no h- acing class oom ange be ween 15 and 21 ◦C and in he
sou h- acing one be ween 16 and 19 ◦C, wi h a s anda d de ia ion o close o 1 ◦C. In case 2 (wi h a sligh ly ha she win e clima e), he
s anda d de ia ion and he minimum empe a u e in he no h- acing class oom a e simila o hose in case 1 (15 ◦C), while he
minimum empe a u e in he sou h- acing class oom is much highe (20 ◦C), and he maximum empe a u es ise o 24 ◦C in bo h he
Table 6
S a is ical analysis o indoo a iables. Mild season (occupied hou s, 2022–2023).
Case Va iable CO 2
[ppm]
PM2,5
[µg/m
3
]
PM10
[µg/m
3
]
Tempe a u e
[ºC]
Rela i e humidi y
[%]
S1.N
Minimum
400
2.00
2.00
16.90
16.00
A e age
668
11.76
12.85
22.30
43.35
Median
637
11.00
13.00
22.50
45.00
Maximum
2066
28.00
32.00
26.70
57.00
S anda d de ia ion
169
2.40
2.79
1.59
7.80
S1.S
Minimum
403
9.00
9.00
18.10
19.00
A e age
711
15.21
16.41
22.90
42.84
Median
659
15.00
16.00
23.00
44.00
Maximum
2243
33.00
37.00
26.00
58.00
S anda d de ia ion
221
2.13
2.29
1.39
7.56
S2.N
Minimum
400
8.00
10.00
14.50
21.00
A e age
818
16.60
18.05
22.35
42.40
Median
718
16.00
17.00
22.60
41.00
Maximum
3127
63.00
76.00
26.80
69.00
S anda d de ia ion
341
4.19
4.88
1.64
9.78
S2.S
Minimum
400
8.00
8.00
17.60
22.00
A e age
922
15.71
17.27
23.38
41.08
Median
770
15.00
16.00
23.60
40.00
Maximum
4792
121.00
141.00
27.20
63.00
S anda d de ia ion
483
5.99
7.13
1.54
10.01
S3.E
Minimum
400
0.00
0.00
17.20
14.00
A e age
864
4.51
4.76
22.99
42.15
Median
685
3.00
3.00
23.00
42.00
Maximum
4098
44.00
78.00
27.40
60.00
S anda d de ia ion
540
4.59
5.21
1.62
8.58
S3.W
Minimum
400
9.00
9.00
16.80
13.00
A e age
822
15.94
17.36
23.44
41.76
Median
684
15.00
16.00
23.30
42.00
Maximum
4067
45.00
49.00
28.00
61.00
S anda d de ia ion
460
3.43
3.80
1.78
8.31
* Values wi hin he es ablished limi s (shown in Table 4) a e ma ked in g een, and hose ou side he limi s
a e ma ked in ed.
R. Escand´
on e al.
Case S udies in The mal Enginee ing 72 (2025) 106335
8
no h- and sou h- acing class ooms. In case 3 ( he mos se e e win e clima e), he minimum indoo empe a u e alues a e he lowes ,
below 13 ◦C in bo h class ooms, bu he maximums a e sligh ly highe han in case 2 (24.5 ◦C in bo h class ooms). The s anda d
de ia ions a e also sligh ly highe han hose de ec ed in cases 1 and 2, app oaching 2 ◦C. Almos all cases (43–46 %) display simila
mean alues o ela i e humidi y, excep S2.S which ises o 57 %. S anda d de ia ions ange be ween 5 and 12 %.
As ou doo condi ions become colde , a e age CO
2
le els ise sligh ly in all cases. The a e age alues a e a ound 850–900 ppm in
all class ooms, app oaching he no ma i e limi s. The maximum alues measu ed exceed 2500 ppm in all cases, e en eaching 5000
ppm in S3.E, indica ing insu icien en ila ion in all class ooms on ce ain occasions. In his pe iod, he a e age measu ed alues o
pollu an s also ise, albei e y sligh ly, wi h PM
2.5
anging om 7
μ
g/m
3
(case S3.E) o 17
μ
g/m
3
(S2.N) and PM
10
om 7 o 19
μ
g/m
3
,
al hough he alues emain adequa e.
A compa ison o he esul s ob ained wi h o he simila s udies in he Medi e anean con ex , shows ha in summe Miao e al. [41]
de ec a simila a e age CO
2
alue (593 ppm) in Ca alu˜
na (no he n Spain), bu a highe maximum (4015 ppm) han hose de ec ed in
his analysis in sou he n Spain. Indoo empe a u es, bo h a e age (28.22 ◦C) and maximum (35.33 ◦C), a e also highe in Ca alu˜
na,
p obably as a esul o less in ensi e en ila ion han ha p esen ed in his s udy. Howe e , in mild seasons, he maximum CO
2
alue
measu ed by Miao e al. (2446 ppm) is simila o ha measu ed in case 1 in sou he n Spain, and much lowe han hose de ec ed in
cases 2 and 3 o his s udy, wi h a e y simila a e age empe a u e (22.7 ◦C) and a somewha highe maximum empe a u e (29.7 ◦C).
Simila a e age alues o CO
2
(557 ppm) and indoo empe a u es (23 ◦C) a e measu ed a he end o June in Ex emadu a (Spain)
[42].
The p oblem o summe o e hea ing in schools is ecu en also in o he clima es, agg a a ed by high occupancy and inadequa ely
con olled na u al en ila ion. In clima es wi h mo e bene icial ou doo empe a u es, such as England, Mohamed e al. [58] epo
indoo empe a u es up o 27 ◦C, wi h CO
2
le els abo e 1000 ppm. In ho and humid clima es, Haddad e al. [59] ound a e age indoo
empe a u es in I an o almos 27 ◦C and CO
2
le els abo e 1400 ppm, and Cai e al. [60] in China egis e ed he same a e age indoo
empe a u e wi h CO
2
le els sligh ly highe (abo e 1500 ppm).
In win e in Pisa (I aly), To iani e al. [43] measu ed an a e age CO
2
le el o 1490 ppm, and a maximum alue o 3899 ppm, wi h
an a e age indoo empe a u e o 21.5 ◦C and a maximum o 27.4 ◦C. These CO
2
alues a e in line wi h hose de ec ed in Ca alu˜
na
(no he n Spain) by Miao e al. [41], wi h an a e age le el o 1194 ppm and a sligh ly highe maximum o 4950 ppm. A simila a e age
Table 7
S a is ical analysis o indoo a iables. Hea ing season (occupied hou s, 2022–2023).
Case Va iable
CO
2
[ppm]
PM
2,5
[µg/m
3
]
PM
10
[µg/m
3
]
Tempe a u e
[ºC]
Rela i e humidi y
[%]
S1.N
Minimum
420
4.00
4.00
14.80
24.00
A e age
835
11.35
12.35
18.58
45.86
Median
734
11.00
12.00
18.80
46.00
Maximum
2751
110.00
141.00
21.10
70.00
S anda d de ia ion
315
4.54
6.15
1.27
9.13
S1.S
Minimum
402
9.00
9.00
16.20
23.00
A e age
913
15.39
16.82
19.31
45.75
Median
798
15.00
16.00
19.40
46.00
Maximum
3934
96.00
127.00
21.60
69.00
S anda d de ia ion
396
5.13
6.74
1.16
8.51
S2.N
Minimum
401
8.00
8.00
15.10
23.00
A e age
883
17.23
18.75
20.68
44.93
Median
776
16.00
17.00
20.60
46.00
Maximum
3359
92.00
104.00
23.80
84.00
S anda d de ia ion
392
4.52
5.23
1.25
12.36
S2.S
Minimum
441
11.00
12.00
20.05
45.00
A e age
902
15.72
17.14
21.79
56.79
Median
691
15.00
16.00
22.10
55.00
Maximum
3907
49.00
55.00
24.00
66.00
S anda d de ia ion
537
3.90
4.38
1.10
4.88
S3.E
Minimum
400
0.00
0.00
12.80
24.00
A e age
911
6.84
7.24
19.35
43.37
Median
680
5.00
5.00
19.40
42.00
Maximum
5000
68.00
114.00
24.50
66.00
S anda d de ia ion
601
5.58
6.34
2.04
9.72
S3.W
Minimum
400
9.00
9.00
12.60
24.00
A e age
907
16.73
18.26
19.77
43.07
Median
684
16.00
17.00
19.70
41.00
Maximum
4067
111.00
206.00
24.40
67.00
S anda d de ia ion
598
4.28
5.26
1.73
9.48
* Values wi hin he es ablished limi s (shown in Table 4) a e ma ked in g een, and hose ou side he limi s
a e ma ked in ed.
R. Escand´
on e al.
Case S udies in The mal Enginee ing 72 (2025) 106335
9
Funding
The au ho s wish o acknowledge he inancial suppo p o ided by G an (PID2020-117722RB-I00) “Re o i en ila ion s a egies
o heal hy and com o able schools wi hin a nea ly ze o-ene gy building ho izon” unded by MICIU/AEI/10.13039/501100011033/.
Escand´
on also acknowledges he inancing o he VI PPIT-US, h ough he 2020 Call o Con ac s o Access o he Spanish Science,
Technology and Inno a ion Sys em o he De elopmen o he Own R&D&I P og am o he Uni e si y o Se ille.
Decla a ion o compe ing in e es
The au ho s decla e ha hey ha e no known compe ing inancial in e es s o pe sonal ela ionships ha could ha e appea ed o
in luence he wo k epo ed in his pape .
Da a a ailabili y
Da a will be made a ailable on eques .
Re e ences
[1] M.A. William, M.J. Su´
a ez-L´
opez, S. Sou ullo, A.A. Hana y, E alua ing hea ing, en ila ion, and ai -condi ioning sys ems owa d minimizing he ai bo ne
ansmission isk o muco mycosis and COVID-19 in ec ions in buil en i onmen , Case S ud. The m. Eng. 28 (2021) 101567, h ps://doi.o g/10.1016/j.
csi e.2021.101567.
[2] Eu opean Commission, COMMUNICATION FROM THE COMMISSION he Eu opean G een Deal, COM, 2019, 640 inal, h ps://eu -lex.eu opa.eu/legal-con en /
EN/TXT/?u i=CELEX%3A52019DC0640.
Fig. 9. Pe cen age o occupied hou s acco ding o cogni i e pe o mance loss (CPL ). 2022–2023 school yea .
Fig. 10. Pe cen age o occupied hou s acco ding o cogni i e pe o mance loss (CPL ). Cooling season.
R. Escand´
on e al.
Case S udies in The mal Enginee ing 72 (2025) 106335
16
[3] Y. Fang, X. Luo, J. Lu, A e iew o esea ch on he impac o he class oom physical en i onmen on schoolchild en’s heal h, J. Build. Eng. 65 (2023) 105430,
h ps://doi.o g/10.1016/j.jobe.2022.105430.
[4] S. Fe a i, T. Bl´
azquez, R. Ca delli, E. De Angelis, G. Puglisi, R. Escand´
on, R. Su´
a ez, Ai change a es and in ec ion isk in school en i onmen s: moni o ing
na u ally en ila ed class ooms in a no he n I alian u ban con ex , Heliyon 9 (2023) e19120, h ps://doi.o g/10.1016/j.heliyon.2023.e19120.
[5] S. Fe a i, T. Bl´
azquez, R. Ca delli, G. Puglisi, R. Su´
a ez, L. Mazza ella, Ven ila ion s a egies o educe ai bo ne ansmission o i uses in class ooms: a
sys ema ic e iew o scien i ic li e a u e, Build. En i on. 222 (2022) 109366, h ps://doi.o g/10.1016/j.builden .2022.109366.
[6] Y.P. Villa eal, R. Pe˜
nabaena-Niebles, C. Be dugo, In luence o en i onmen al condi ions on s uden s’ lea ning p ocesses: a sys ema ic e iew, Build. En i on.
231 (1) (2023) 110051, h ps://doi.o g/10.1016/j.builden .2023.110051.
[7] L. Cha zidiakou, D. Mumo ic, A. Summe ield, Is CO
2
a good p oxy o indoo ai quali y in class ooms? Pa 1: he in e ela ionships be ween he mal
condi ions, CO
2
le els, en ila ion a es and selec ed indoo pollu an s, Build. Se . Eng. Technol. 36 (2) (2015) 129–161, h ps://doi.o g/10.1177/
014362441456624.
[8] O. Ramalho, G. Wya , C. Mandin, P. Blondeau, e al., Associa ion o ca bon dioxide wi h indoo ai pollu an s and exceedance o heal h guideline alues, Build.
En i on. 93 (2015) 115–124, h ps://doi.o g/10.1016/j.builden .2015.03.018.
[9] L. S abile, M. Dell’ Isola, A. Russi, A. Massimo, G. Buonanno, The e ec o na u al en ila ion s a egy on indoo ai quali y in schools, Sci. To al En i on. 595
(2017) 894–902, h ps://doi.o g/10.1016/j.sci o en .2017.03.048.
[10] N. Coope , D. G een, Y. Guo, S. Va doulakis, School child en’s exposu e o indoo ine pa icula e ma e , En i on. Res. Le . 15 (2020) 115003. h ps://
iopscience.iop.o g/a icle/10.1088/1748-9326/abba e.
[11] T.A. Jacobson, J.S. Kle , M.T. He nke, R.K. B aun, K.C. Meye , W.E. Funk, Di ec human heal h isks o inc eased a mosphe ic ca bon dioxide, Na . Sus ain. 2
(2019) 691–701, h ps://doi.o g/10.1038/s41893-019-0323-1.
[12] H. Bu sche , K. Schüepp, The occu ence o ul a ine pa icles in he speci ic en i onmen o child en, Paedia . Respi . Re . 13 (2012) 89–94, h ps://doi.o g/
10.1016/j.p .2011.07.004.
[13] T. Sal hamme , E. Uhde, T. Sch ipp, A. Schieweck, e al., Child en’s well-being a schools: impac o clima ic condi ions and ai pollu ion, En i on. In . 94
(2016) 196–210, h ps://doi.o g/10.1016/j.en in .2016.05.009.
[14] S. Holga e, J. G igg, H. A shad, e al., Heal h e ec s o indoo ai quali y on child en and young people, in: R.M. Ha ison (Ed.), En i onmen al Pollu an
Exposu es and Public Heal h, The Royal Socie y o Chemis y, 2020, pp. 151–188. h ps://pubs. sc.o g/en/con en /chap e /bk9781788018951-00151/978-1-
78801-895-1.
[15] T. Schibuola, C. Tambani, Indoo en i onmen al quali y classi ica ion o school en i onmen s by moni o ing PM and CO
2
concen a ion le els, A mos. Pollu .
Res. 11 (2) (2020) 332–342, h ps://doi.o g/10.1016/j.ap .2019.11.006.
[16] R. Mi al, R. Ni, J.H. Seo, The low physics o COVID-19, J. Fluid Mech. 894 (2020) F2, h ps://doi.o g/10.1017/j m.2020.330.
[17] G. Buonanno, G. Ma ks, L. Mo awska, Heal h e ec s o daily ai bo ne pa icle dose in child en: di ec associa ion be ween pe sonal dose and espi a o y heal h
e ec s, En i on. Pollu . 180 (2013) 246–250, h ps://doi.o g/10.1016/j.en pol.2013.05.039.
[18] S. Pe e sen, K. Jensen, A. Pede sen, H. Rasmussen, The e ec o inc eased class oom en ila ion a e indica ed by educed CO2 concen a ion on he
pe o mance o schoolwo k by child en, Indoo Ai 26 (2016) 366–379, h ps://doi.o g/10.1111/ina.12210.
[19] P. Wa gocki, J.A. Po as-Salaza , S. Con e as-Espinoza, W. Bahn le h, The ela ionships be ween class oom ai quali y and child en’s pe o mance in school,
Build. En i on. 173 (2020) 106749, h ps://doi.o g/10.1016/j.builden .2020.106749.
[20] Ge man Fede al En i onmen Agency, Hygienic guide alues om he Ge man commi ee on indoo ai guide alues, A ailable a : h ps://www.
umwel bundesam .de/si es/de aul / iles/medien/4031/bilde /da eien/0_hygienic_guide_ alues_20220704_en.pd , 2022.
[21] Ame ican Socie y o Hea ing, Re ige a ing and Ai -Condi ioning Enginee s (ASHRAE), ASHRAE 62.1: Ven ila ion and Accep able Indoo Ai Quali y, ASHRAE,
2022.
[22] Eu opean Commi ee o S anda iza ion (CEN), EN 16798-1: 2019, pa 1: indoo en i onmen al inpu pa ame e s o design and assessmen o ene gy
pe o mance o buildings add essing indoo ai quali y. The mal En i onmen , Ligh ing and Acous ics, CEN, 2019.
[23] F. Babich, G. To iani, J. Co ona, I. La a-Ibeas, Compa ison o indoo ai quali y and he mal com o s anda ds and a ia ions in exceedance o school
buildings, J. Build. Eng. 71 (2023) 106405, h ps://doi.o g/10.1016/j.jobe.2023.106405.
[24] W.J. Fisk, The en ila ion p oblem in schools: li e a u e e iew, Indoo Ai 27 (2017) 1039–1051, h ps://doi.o g/10.1111/ina.12403.
[25] L. Cha zidiakou, D. Mumo ic, A.J. Summe ield, Wha do we know abou indoo ai quali y in school class ooms? A c i ical e iew o he li e a u e, In ell. Build.
In . 4 (2012) 228–259, h ps://doi.o g/10.1080/17508975.2012.725530.
[26] C. He acleous, A. Michael, Expe imen al assessmen o he impac o na u al en ila ion on indoo ai quali y and he mal com o condi ions o educa ional
buildings in he Eas e n medi e anean egion du ing he hea ing pe iod, J. Build. Eng. 26 (2019) 100917, h ps://doi.o g/10.1016/j.jobe.2019.100917.
[27] P.V. Do izas, M.N. Assimakopoulos, C. Helmis, M. San amou is, An in eg a ed e alua ion s udy o he en ila ion a e, he exposu e and he indoo ai quali y in
na u ally en ila ed class ooms in he medi e anean egion du ing sp ing, Sci. To al En i on. 502 (2015) 557–570, h ps://doi.o g/10.1016/j.
sci o en .2014.09.060.
[28] M. Gil-Baez, J. Lizana, J.A. Bece a Villanue a, M. Molina-Huel a, A. Se ano-Jimenez, R. Chaca egui, Na u al en ila ion in class ooms o heal hy schools in
he COVID e a in medi e anean clima e, Build. En i on. 206 (2021) 108345, h ps://doi.o g/10.1016/j.builden .2021.108345.
[29] M. San amou is, Expe imen al in es iga ion o he ai low and indoo ca bon dioxide concen a ion in class ooms wi h in e mi en na u al en ila ion, Ene gy
Build. 40 (10) (2008) 1833–1843, h ps://doi.o g/10.1016/j.enbuild.2008.04.002.
[30] D.A. K awczyk, A. Rode o, K. Gładyszewska-Fiedo uk, A. Gajewski, CO
2
concen a ion in na u ally en ila ed class ooms loca ed in di e en
clima es—Measu emen s and simula ions, Ene gy Build. 129 (2016) 491–498, h ps://doi.o g/10.1016/j.enbuild.2016.08.003.
[31] S. Kephalopoulos, ´
E. Csobod, E. de Oli ei a Fe nandes, Guidelines o heal hy en i onmen s wi hin Eu opean schools. SINPHONIE Schools Indoo Pollu ion and
Heal h Obse a o y Ne wo k in Eu ope, Publica ions O ice o he Eu opean Union, Luxembou g, 2014, h ps://doi.o g/10.2788/89936.
[32] H.B. S age, J. Shingle on, S. Ghosh, F. Sca abel, L. Pellis, T. Finnie, Shu and e-open: he ole o schools in he sp ead o Co id-19 in Eu ope, Eu opePhil. T ans.
R. Soc. (2021) B37620200277, h ps://doi.o g/10.1098/ s b.2020.0277.
[33] J. Allen, J. Spengle , E. Jones, J. Cedeno-Lau en , 5-s ep Guide o Checking Ven ila ion Ra es in Class ooms, Ha a d Heal hy Buildings p og am, 2020.
A ailable a : h ps://schools. o heal h.o g/wp-con en /uploads/si es/19/2020/10/Ha a d-Heal hy-Buildings-p og am-How- o-assess-class oom- en ila ion-
10-30-2020.pd -EN.pd .
[34] Wo ld Heal h O ganiza ion, Conside a ions in Adjus ing Public Heal h and Social Measu es in he Con ex o COVID-19 Wo ld Heal h O ganisa ion In e im
Guidance, ols. 1–7, 2020.
[35] S. Pa k, Y. Choi, D. Song, E.K. Kim, Na u al en ila ion s a egy and ela ed issues o p e en co ona i us disease 2019 (COVID-19) ai bo ne ansmission in a
school building, Sci. To al En i on. 789 (2021) 147764, h ps://doi.o g/10.1016/j.sci o en .2021.147764.
[36] M.T. Mi anda, P. Rome o, V. Vale o-Ama o, J.I. A anz, I. Mon e o, Ven ila ion condi ions and hei in luence on he mal com o in examina ion class ooms in
imes o COVID-19. A case s udy in a Spanish a ea wi h Medi e anean clima e, In . J. Hyg En i on. Heal h 240 (2022) 113910, h ps://doi.o g/10.1016/j.
ijheh.2021.113910.
[37] A. Alonso, J. Llanos, R. Escand´
on, J.J. Send a, E ec s o he co id-19 pandemic on indoo ai quali y and he mal com o o p ima y schools in win e in a
medi e anean clima e, Sus ain. Times 13 (5) (2021) 2699, h ps://doi.o g/10.3390/su13052699.
[38] F. Villanue a, A. No a io, B. Caba˜
nas, P. Ma ín, S. Salgado, M.F. Gab iel, Assessmen o CO
2
and ae osol (PM
2.5
, PM
10
, UFP) concen a ions du ing he
eopening o schools in he COVID-19 pandemic: he case o a me opoli an a ea in cen al-sou he n Spain, En i on. Res. 197 (2021) 111092, h ps://doi.o g/
10.1016/j.en es.2021.111092.
[39] A.J. Aguila , M.L. De La Hoz-To es, M.D. Ma ínez-Ai es, D.P. Ruiz, Moni o ing and assessmen o indoo en i onmen al condi ions a e he implemen a ion o
COVID-19-Based en ila ion s a egies in an educa ional building in Sou he n Spain, Senso s 21 (2021) 7223, h ps://doi.o g/10.3390/s21217223.
R. Escand´
on e al.
Case S udies in The mal Enginee ing 72 (2025) 106335
17
[40] T. Lipinski, D. Ahmad, N. Se ey, H. Jouha a, Re iew o en ila ion s a egies o educe he isk o disease ansmission in high occupancy buildings, In . J.
The mo luids 7–8 (2020) 100045, h ps://doi.o g/10.1016/j.ij .2020.100045.
[41] S. Miao, M. Gangolells, B. Tejedo , A comp ehensi e assessmen o indoo ai quali y and he mal com o in educa ional buildings in he medi e anean clima e,
Indoo Ai 2023 (2023) 649829, h ps://doi.o g/10.1155/2023/6649829.
[42] P. Rome o, V. Vale o-Ama o, M.T. Mi anda, Indoo ai quali y and he mal com o in uni e si y class ooms in Sou hwes e n Spain: a longi udinal analysis om
pandemic o pos -pandemic, Buildings 15 (5) (2025) 829, h ps://doi.o g/10.3390/buildings15050829.
[43] G. To iani, G. Lambe i, F. Fan ozzi, F. Babich, Explo ing he impac o pe cei ed con ol on he mal com o and indoo ai quali y pe cep ion in schools,
J. Build. Eng. 63 (1) (2023) 105419, h ps://doi.o g/10.1016/j.jobe.2022.105419. Pa A.
[44] L. Jia, J. Han, X. Chen, Q. Li, C. Lee, Y. Fung, In e ac ion be ween he mal com o , indoo ai quali y and en ila ion ene gy consump ion o educa ional
buildings: a comp ehensi e e iew, Buildings 11 (12) (2021) 591, h ps://doi.o g/10.3390/buildings11120591.
[45] J. Llanos-Jim´
enez, R. Su´
a ez, A. Alonso, J.J. Send a, A che ypes o public seconda y schools in medi e anean clima e. Indoo ai quali y and com o ield
s udies. P oceedings o he 42nd AIVC - 10 h Tigh Ven - 8 h Ven icool Con e ence, Ven ila ion challenges in a changing wo ld, Ro e dam, 2022, pp. 808–817.
[46] Spanish Go e nmen . CTE, C´
odigo T´
ecnico de la Edi icaci´
on, Documen o B´
asico De Aho o De Ene gía, Spanish Go e nmen , 2006. A ailable a : h ps://www.
codigo ecnico.o g/Documen osCTE/Aho oEne gia.h ml.
[47] Spanish Go e nmen , NBE-CT-79, No ma B´
asica de la Edi icaci´
on. Condiciones T´
e micas En Los Edi icios, Spanish Go e nmen , 1979. A ailable a : h ps://
www.boe.es/boe/dias/1979/10/22/pd s/A24524-24550.pd .
[48] Eu opean Commi ee o S anda iza ion (CEN), EN ISO 7726:1998, E gonomics o he The mal En i onmen Ins umen s o Measu ing Physical Quan i ies,
CEN, 1998.
[49] Eu opean Commi ee o S anda iza ion (CEN), EN ISO 16000-26:2012, Indoo Ai - Pa 26: Sampling S a egy o Ca bon Dioxide (CO2), CEN, 2012.
[50] Spanish Go e nmen . RITE, Reglamen o De Ins alaciones T´
e micas En Los Edi icios, Spanish Go e nmen , 2021. A ailable a : h ps://www.boe.es/boe/dias/
2021/03/24/pd s/BOE-A-2021-4572.pd .
[51] Eu opean Commi ee o S anda iza ion (CEN), EN 16798-3:2017, ene gy pe o mance o buildings. Ven ila ion o Buildings o Non- esiden ial Pe o mance
Requi emen s Ven ila ion and oom-condi ioning Sys ems, CEN, 2017.
[52] Wo ld Heal h O ganiza ion (WHO), Global Ai Quali y Guidelines: Pa icula e Ma e (PM
2. 5
and PM
10
), Ozone, Ni ogen Dioxide, Sul u Dioxide and Ca bon
Monoxide, WHO, Copenhagen, Denma k, 2021.
[53] K. Run, F. C´
e a¨
e , J.F. Dub´
e, In luence o ansien condi ions on he mal com o e alua ions: ield s udy in uni e si y buildings, Case S ud. The m. Eng. 66
(2025) 105737, h ps://doi.o g/10.1016/j.csi e.2024.105737.
[54] ASTM, S anda d Guide o Using Indoo Ca bon Dioxide Concen a ions o E alua e Indoo Ai Quali y and Ven ila ion, ASTM In e na ional, Wes
Conshohocken, PA, USA, 2012.
[55] S. Ba e man, Re iew and ex ension o CO2-based me hods o de e mine en ila ion a es wi h applica ion o school class ooms, In . J. En i on. Res. Publ.
Heal h 14 (2) (2017) 145, h ps://doi.o g/10.3390/ije ph14020145.
[56] P. Wa gocki, J.A. Po as-Salaza , S. Con e as-Espinoza, The ela ionship be ween class oom empe a u e and child en’s pe o mance in school, Build. En i on.
157 (2019) 197–204, h ps://doi.o g/10.1016/j.builden .2019.04.046.
[57] J. Dong, Y. Schwa z, I. Ko olija, D. Mumo ic, The impac o clima e change on cogni i e pe o mance o child en in English school s ock: a simula ion s udy,
Build. En i on. 243 (2023) 110607, h ps://doi.o g/10.1016/j.builden .2023.110607.
[58] S. Mohamed, L. Rod igues, S. Ome , J. Calau i , O e hea ing and indoo ai quali y in p ima y schools in he UK, Ene gy Build. 250 (2021) 111291, h ps://doi.
o g/10.1016/j.enbuild.2021.111291.
[59] S. Haddad, P. Osmond, S. King, Re isi ing he mal com o models in I anian class ooms du ing he wa m season, Build. Res. In . 45 (2017) 457–473, h ps://
doi.o g/10.1080/09613218.2016.1140950.
[60] C. Cai, Z. Sun, L.B. Weschle , T. Li, W. Xu, Y. Zhang, Indoo ai quali y in schools in Beijing: ield es s, p oblems and ecommenda ions, Build. En i on. 205
(2021) 108179, h ps://doi.o g/10.1016/j.builden .2021.108179.
R. Escand´
on e al.
Case S udies in The mal Enginee ing 72 (2025) 106335
18
