Assessment of indoor air quality and thermal comfort in Portuguese secondary classrooms: Methodology and results Luísa Dias Pereira a, * , Daniela Raimondo b , Stefano Paolo Corgnati b , Manuel Gameiro da Silva a a ADAI e LAETA, Department of Mechanical Engineering, Rua Luis Reis Santos, University of Coimbra, P olo II, 3030-201 Coimbra, Portugal b TEBE Research Group, Department of Energy, Politecnico di Torino, corso Duca degli Abruzzi 24,10129 Torino, Italy article info Article history: Received 31 March 2014 Received in revised form 5 June 2014 Accepted 10 June 2014 Available online 23 June 2014 Keywords: Indoor air quality Thermal comfort Metabolic carbon dioxide School PMV/PPD indices abstract This work shows the results of a field study about indoor thermal comfort, based on investigations in Portuguese secondary schools' classrooms. The surveys herein presented were carried out in a school in Beja, in the South-East of Portugal. The field study was conducted by physical parameters monitoring and survey questionnaires. Both field monitoring and subjective surveys were performed at the same time during the regular class period (either at the end or at the beginning of the class). The measurement campaign consisted in measuring the environmental parameters e air temperature (T a ), air relative humidity (RH), CO 2 concentrations. Outdoor air temperature values were registered hourly at the nearest climatological station. Through these data, along with the actual people clothing and metabolic rate being know, both Fanger's comfort indices were calculated (predicted mean vote and predicted percentage of dissatisfied people). The subjective survey investigated the thermal acceptability, the thermal sensation and the thermal preference. The judgments about the thermal environment were compared with the results of the field mea- surements. Draught preference votes, air stiffness and global air quality votes were also collected. The results show that the students found temperature range beyond the comfort zone acceptable, and revealed the occupants' accommodation to CO 2 exposure, confirming the results obtained in other studies. Moreover, it was verified that running on naturally ventilation mode, CO 2 concentration limits were highly exceeded. © 2014 Elsevier Ltd. All rights reserved. 1. Introduction Indoor Environment Comfort results on the combination of four major environmental factors, such as Thermal Comfort (TC), Indoor Air Quality (IAQ), Acoustic Comfort (AC) and Visual Comfort (VC) [1]. Thermal comfort in schools (classrooms) has lately been receiving more research attention [2e5]. Either because indoor environmental quality (IEQ) has a repercussion on buildings' en- ergy use [3] but also because this might condition students and teachers performance [6e12]. On the latest case some research has been developed but most studies are not very conclusive or show limited evidence, recalling further investigation [6,8,13]. Assessing occupants' satisfaction about the indoor environment has been common practice for evaluating thermal comfort (TC) and indoor air quality (IAQ) perception [14e16]. In this context, an empirical study has been driven in a Portuguese school focusing on these two factors: TC and IAQ. Monitoring parameters were faced up with perceived TC and IAQ responses. Field research, or «the analysis of “real-world”» [3] is important to test the validity of the PMV (Predicted Mean Vote), that provides the basis of the main thermal comfort standards [17,18]. Several field studies have been investigating the thermal sensation votes (TSV) regarding the indoor thermal environment (ITE). In various cases it has been found that people in naturally ventilated indoor environments are comfortable within a larger range of values than in fully conditioned environments. In warm climate it has even been shown that people can achieve comfort at higher temperatures, compared to the recommendations based on PMV calculation [19]. The work herein presented aims at evaluating TC and IAQ in a recently refurbished school running in free running conditions/ natural ventilation mode during the mid-season. In this study, the comparison between the subjective votes (TSV) and predicted * Corresponding author. Tel.: þ351 239 790 729; fax: þ351 239 790 771. E-mail address: luisa.pereira@uc.pt (L. Dias Pereira). Contents lists available at ScienceDirect Building and Environment journal homepage: www.elsevier.com/locate/buildenv http://dx.doi.org/10.1016/j.buildenv.2014.06.008 0360-1323/© 2014 Elsevier Ltd. All rights reserved. Building and Environment 81 (2014) 69e80