title: An integrated evaluation study of the ventilation rate, the exposure and the indoor air quality in naturally ventilated classrooms in the Mediterranean region during spring.
abstract: Ventilation rates and indoor air pollutants have been extensively monitored in nine naturally ventilated primary schools of Athens, Greece during spring. The ventilation rates and pollutant levels were studied during the teaching and non-teaching periods and ventilation profiles were created for each of the schools. The median ventilation rates per school ranged between 0.7 and 8 ACH while the average ventilation rate in all schools (11.7l/s/p) was greater than the minimum recommended rates by ASHRAE for school classrooms. The average carbon dioxide (CO2) concentrations per school varied between 893 and 2082ppm, while the majority of the cases were slightly above the recommended limit values. CO2 concentrations were also positively correlated to the number of students and negatively correlated to the ventilation rates. Particles of several size ranges (PM10, PM5, PM2.5, PM1, PM0.5 and UFP) were also measured and analyzed. PM10 concentrations exceeded the recommended limit values by more than 10 times for the majority of the cases. There were also many cases that the PM2.5 concentrations exceeded their limit values. PM concentrations were significantly affected by the ventilation rates and the presence of students. All of the measured particle sizes were greater during teaching than the non-teaching hours. For most of the cases the indoor to outdoor (I/O) concentrations ratios of PM10 and PM2.5 were much greater than one, indicating that the indoor environment was being mostly affected by indoor sources instead of the outdoor air. Furthermore it was found that chalk and marker boards' usage significantly affect indoor pollutant concentrations. Overall, the measured levels of exposure were for most of the cases greater than the recommended guideline values due to the intense presence of indoor pollution sources, even though the ventilation rates were in general satisfactory.
authors.affiliation: Faculty of Physics, Departments of Environmental Physics and Meteorology, University of Athens, University Campus, Athens, 157 84, Greece. Electronic address: pdoriza@phys.uoa.gr.
authors.forename: Paraskevi Vivian
authors.initials: PV
authors.lastname: Dorizas
authors.affiliation: Faculty of Physics, Departments of Environmental Physics and Meteorology, University of Athens, University Campus, Athens, 157 84, Greece.
authors.forename: Margarita-Niki
authors.initials: MN
authors.lastname: Assimakopoulos
authors.affiliation: Faculty of Physics, Departments of Environmental Physics and Meteorology, University of Athens, University Campus, Athens, 157 84, Greece.
authors.forename: Constantinos
authors.initials: C
authors.lastname: Helmis
authors.affiliation: Faculty of Physics, Departments of Environmental Physics and Meteorology, University of Athens, University Campus, Athens, 157 84, Greece.
authors.forename: Mattheos
authors.initials: M
authors.lastname: Santamouris
mesh_terms: D000393:Air Pollutants / Q000032:analysis; D016902:Air Pollution, Indoor / Q000032:analysis* / Q000706:statistics & numerical data; D004784:Environmental Monitoring; D006801:Humans; D019570:Inhalation Exposure / Q000032:analysis* / Q000706:statistics & numerical data; D019083:Mediterranean Region; D052638:Particulate Matter / Q000032:analysis; D012574:Schools / Q000706:statistics & numerical data*; D012621:Seasons; D014691:Ventilation
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter
keywords: CO(2); Health; IAQ; Naturally ventilated schools; PM; Ventilation