Association between substandard classroom ventilation rates and students' academic achievement

Description of air quality and environmental characteristics in primary school classrooms in the Community of Madrid

INTRODUCTION

Air quality in schools is a concern at the European level, and few data have been published on the subject in the Community of Madrid.

MATERIAL AND METHODS

We conducted a longitudinal descriptive study on the presence and distribution of pollutants in four schools in Madrid selected on account of their location, exposure to traffic and proximity to green areas. We measured pollutants and assessed environmental characteristics in primary school classrooms. We measured pollutants with sensors over five data collection campaigns, each lasting two weeks. The obtained data were analyzed with the R software. We calculated the median, range and percentage of exceedance of recommended thresholds and assessed environmental conditions.

RESULTS

We found levels of 2.5 µm particulate matter (PM) above the recommended threshold in 40%-70% of the measurements. Volatile organic compounds (VOCs) exceeded the recommended threshold in April in 41.52% of the measurements. The level of CO2 exceeded the recommended threshold in three of the campaigns. There was broad variation in ultrafine particles. Temperature, CO2, VOCs, PM 1, PM 0.3 and PM 2.5 levels were higher in occupied classrooms. Humidity was positively correlated to PM 0.3, PM 1 and PM 2.5 levels and negatively correlated to ultrafine particle levels.

CONCLUSIONS

This is the first study to assess indoor pollutants and their concentration in schools in the Madrid region. We found levels of CO2, PM 2.5 and VOCs exceeding the currently recommended thresholds.

How to improve the perceived health, comfort, and well-being of primary school teachers? A quantitative self-reported survey during the COVID-19 pandemic in Scotland

Teachers are among the most stressed professionals, for whom the built environment has an influence. In addition, the COVID-19 pandemic has increased the pressure on schools, where enhanced ventilation is deemed essential to help reduce virus-laden particles in classrooms. Good Indoor Air Quality (IAQ) is required to maintain an adequate level of comfort, health, and well-being. Therefore, solutions to improve IAQ quickly and cheaply are essential. As such, the Scottish Government has funded Local Authorities to purchase CO2 sensors for school classrooms. This study explores two interventions designed to improve the quality of indoor air. The first one by raising the awareness of the teachers on ventilation strategies via a webinar. The second one by deploying devices that visually inform the occupants of the indoor conditions: Temperature, Relative Humidity, and CO2 levels in the classrooms. The novelty of this study is that it evaluated the influence of engaging teachers in the management of their working indoor environments. This paper presents the results of the perceived health, comfort, and well-being of teachers from two primary schools built before 1919 located in Edinburgh, Scotland. Visual feedback sensors improved the perceived air quality of teachers in their classrooms but increased pressure on their workload and were a potential distraction for their pupils. In contrast, raising the awareness of the teachers via the webinar improved their perception of their indoor environment without added pressure. Therefore, awareness programs should be devised to educate school staff on Indoor Air Quality in addition to the development of sensors with visual feedback.

Risk of infection due to airborne virus in classroom environments lacking mechanical ventilation

The COVID-19 pandemic highlighted the role of indoor environments on disease transmission. However, our understanding of how transmission occurred evolved as the pandemic progressed. Enclosed spaces where pathogen-laden aerosols accumulate were strongly linked to increased transmission events. Most classrooms, particulalry in the U.S., do not have any mechanical ventilation systems but do have many people congregating indoors for long periods of time. Here we employ a safe, non-pathogenic surrogate virus, the bacteriophage phi6, to interrogate aerosol transmission in classroom environments that do not have any natural or mechanical ventilation in order to provide baseline understanding of how effectively aerosols facilitate new infections. We measure exposure risk using a modified passive monitoring technique compliant with applicable standards, including ISO 14698-1:2003. We find that virus-laden aerosols establish new infections over all distances tested within minutes and that the time of exposure did not change transmission rate. We further find that relative humidity, but not temperature nor a UV-based disinfection device, significantly lowered transmission rates. Our data suggest that, even without mechanical ventilation, relative humidity remains an inexpensive and highly effective mitigation strategy while UV air treatment may not.

How teacher behaviors and perceptions, air change rates, and portable air purifiers affect indoor air quality in naturally ventilated schools

Introduction

Many school buildings have inadequate ventilation, rudimentary if any air filtration, and aging and poorly maintained mechanical systems, all of which can lead to poor indoor air quality (IAQ). These issues are especially acute in environmental justice (EJ) communities where schools are located in polluted areas. This community-based participatory research examines how IAQ in naturally ventilated school buildings is affected by the use of air purifiers, air change rates, outdoor pollution levels, and teacher and staff behavior.

Methods

IAQ assessments were performed at two schools in Detroit, Michigan, which included building walk-through inspections and continuous indoor and outdoor measurements of black carbon (BC), particulate matter (PM10 and PM2.5), carbon dioxide (CO2), air change rates (ACRs), temperature, humidity, and sound pressure levels. Air purifiers with usage monitors were then installed, and the IAQ assessments were repeated. Teachers were surveyed before and after purifier deployment.

Results

At baseline, classrooms had low ACRs (0.58-1.38 h-1), moderate PM2.5 levels (2.8-8.9 μg/m3), highly variable PM10 concentrations (4.7-37.5 μg/m3), and elevated BC levels (0.3-0.7 μg/m3), reflecting emissions from local traffic, industry and other sources. The installation and use of purifiers reduced pollutant levels and the overall performance matched the predictions of a single compartment model. However, daily reductions varied widely among classrooms, reflecting differences in teacher behavior regarding the frequency of opening windows and the operation of purifiers, including differences in purifier fan speed settings and whether purifiers were used at night. Survey responses indicated that many teachers were aware of IAQ problems. The higher rates reported for health symptoms and dissatisfaction at one school may have lowered the teachers' tolerance to noise and reduced purifier use.

Discussion

The study helps explain the variation reported in prior studies using purifiers, and it reinforces the need to monitor IAQ and purifier use, use enhanced filtration and increase ventilation, and engage with teachers and school staff to support and maintain IAQ programs in schools.

Health benefits to vulnerable populations by meeting particle-level guidelines inside schools with different ventilation conditions

We conducted simultaneous real-time measurements for particles on the premises of four schools, two of which were naturally ventilated (NV) and two mechanically ventilated (MV) in Kanpur, India. Health to school children from reduced particle levels inside classrooms simulated to the lowest acceptable levels (ISHRAE Class C: PM10 ≤ 100 µg/m3 & PM2.5 ≤ 25 µg/m3) using air filters were examined. Lung deposition of particles was used as a proxy for health impacts and calculated using the MPPD model. The particle levels in all classrooms were above the baseline, with NV classrooms having higher particle masses than MV classrooms: 72.16% for PM1, 74.66% for PM2.5, and 85.17% for PM10. Our calculation reveals a whooping reduction in particles deposited in the lungs (1512% for PM10 and 1485% for PM2.5) in the case of the NV classrooms. Results highlight unhealthy air inside classrooms and suggest urgent interventions, such as simple filtration techniques, to achieve acceptable levels of particles inside schools.

Uncertainties in exposure predictions arising from point measurements of carbon dioxide in classroom environments

Predictions of airborne infection risk can be made based on the fraction of rebreathed air inferred from point measurements of carbon dioxide (CO[Formula: see text]). We investigate the extent to which environmental factors, particularly spatial variations due to the ventilation provision, affect the uncertainty in these predictions. Spatial variations are expected to be especially problematic in naturally ventilated spaces, which include the majority of classrooms in the UK. An idealized classroom, broadly representative of the physics of (buoyancy-driven) displacement ventilation, is examined using computational fluid dynamics, with different ventilation configurations. Passive tracers are used to model both the CO[Formula: see text] generated by all 32 occupants and the breath of a single infectious individual (located in nine different regions). The distribution of infected breath is shown to depend strongly on the distance from the release location but is also affected by the pattern of the ventilating flow, including the presence of stagnating regions. However, far-field exposure predictions based on single point measurements of CO[Formula: see text] within the breathing zone are shown to rarely differ from the actual exposure to infected breath by more than a factor of two-we argue this uncertainty is small compared with other uncertainties inherent in modelling airborne infection risk.

Perspectives and Attitudes of Newer New Jersey High School Teachers towards Cleaning, Sanitizing, and Disinfecting Consumer Products Used in School Classrooms

During the COVID-19 pandemic, there was an increased reported use of chemical cleaning, sanitizing, and disinfecting products (CSDPs), which created public concerns about negative health consequences for both children and adults in public schools. A subset of newer teachers shared experiences regarding safety and health (S&H) while working in school-based settings through a series of online surveys. Surveys were provided to teachers who completed work-based learning supervisory trainings provided by the New Jersey Safe Schools Program between October 2021 and June 2023. The participants answered questions focusing on CSDPs purchased for school use, their attitudes towards CSDPs, their use of personal protective equipment, and symptoms employees may have had due to CSDPs. A total of 205 teacher participants successfully completed the surveys. Over 25% of the teachers did not know where their CSDPs originated from, as they were provided by the school. Most participants "sometimes", "not often", or "never" read labels for CSDP ingredients or looked them up on healthy product apps. The participants (60%) tended to wear gloves while cleaning/disinfecting but did not wear masks. A third of the participants experienced respiratory health problems after working at school. Overall, the data suggest that more education on S&H regarding CSDPs needs to be provided to New Jersey teachers.

Measuring Indoor Air Quality Does Not Prevent COVID-19

Boston Public Schools (BPS) closed for in-person learning in March 2020 due to COVID-19 and didn't fully reopen until the 2021-2022 school year. Due to the age of schools and absent ventilation systems, coupled with decades of disinvestment in the infrastructure, BPS entered the pandemic with serious challenges impacting the health of students and staff. These challenges were magnified by an infectious airborne virus. Instead of using this opportunity to improve ventilation systems, BPS opted to invest in an air quality monitoring system. This system only confirmed what was already known-there is poor ventilation in most school buildings. It did not lead to correction of new or long-standing problems. This failure has harmed the BPS community, which includes primarily low-income Black and Brown families. This article describes Boston's school system, its track record of inadequate attention to infrastructure, and explores pitfalls of focusing on evaluation instead of correction.

Association of School Infrastructure on Health and Achievement Among Children With Asthma

OBJECTIVE

To determine whether school infrastructure is associated with health and academic outcomes among elementary school children with asthma.

METHODS

We conducted a retrospective cohort study of linked medical, academic, and facilities data from a large mid-Atlantic school district of the United States. All K-5 students with asthma who were enrolled under the state's Children's Health Insurance Program were included. We estimated associations of the infrastructure quality of the student's school, as assessed by an engineering firm in Summer 2011 and represented by the Facility Condition Index (FCI), with asthma health outcomes, absenteeism, and standardized test scores in math and reading in the 2 academic years thereafter.

RESULTS

A total of 6558 students were identified, the majority non-Hispanic Black, across 130 schools. Most schools (97/130, 75%) were in very poor or worse condition. In cluster-adjusted models accounting for demographics, grade, school-specific area deprivation, and inhaled corticosteroid use, a one standard deviation increase in FCI, corresponding to greater infrastructure deficiency, was associated with higher rates of asthma-related hospitalizations (incidence rate ratio [IRR] 1.16; 95% confidence interval [CI] 1.03, 1.32), more absenteeism (IRR 1.05; 95% CI 1.01, 1.08), and lower scores in math (mean difference [MD] -3.3; 95% CI -5.5, -1.2) and reading (MD -3.0; 95% CI -5.1, -0.9). There were no differences in rates of asthma-related emergency visits or steroid prescriptions.

CONCLUSIONS

Children with asthma attending schools with poorer infrastructure had worse health and academic outcomes. Public policy emphasizing reinvestment in school infrastructure may be a potential means of addressing asthma disparities.

Meta-Analysis of the Effect of Ventilation on Intellectual Productivity

Indoor air quality (IAQ) influences the health and intellectual productivity of occupants. This paper summarizes studies investigating the relationship between intellectual productivity and IAQ with varying ventilation rates. We conducted a meta-analysis of five studies, with a total of 3679 participants, and performed subgroup analyses (arithmetic, verbal comprehension, and cognitive ability) based on the type of academic performance. The task performance speed and error rate were evaluated to measure intellectual productivity. The effect size of each study was evaluated using the standardized mean difference (SMD). In addition, we calculated a dose-response relationship between ventilation rate and intellectual productivity. The results show that the task performance speed improved, SMD: 0.18 (95% CI: 0.10-0.26), and the error rate decreased, SMD: -0.05 (95% CI: -0.11-0.00), with an increase in ventilation rate. Converting the intervention effect size on the SMD into the natural units of the outcome measure, our analyses show significant improvements in the task performance speed: 13.7% (95% CI: 6.2-20.5%) and 3.5% (95% CI: 0.9-6.1%) in terms of arithmetic tasks and cognitive ability, respectively. The error rate decreased by -16.1% (95% CI: -30.8-0%) in arithmetic tasks. These results suggest that adequate ventilation is necessary for good performance.

Self-reported voice disorders of teachers and indoor air quality in schools: a cross-sectional study in Finland

OBJECTIVE

We aimed to study the association between self-reported voice disorders among teachers and indoor air quality in school buildings.

METHODS

We performed a questionnaire study of 538 Finnish teachers working in 67 school buildings utilizing both perceived and technical evaluations; the agreement between these two assessments was also studied. The technical assessment was provided by technical experts.

RESULTS

Teachers with voice disorders reported significantly more complaints from indoor air than those without voice disorders. The results also indicated a possible connection between the technical assessment and voice disorders. After adjustment for sex, stress and asthma, the prevalence of voice disorders was 47% higher in teachers working in renovated buildings compared to those working in the non-problem buildings (aRR1.47; CI 95% 1.11-1.95). The prevalence of voice disorders was 28% higher among teachers working in buildings with problems compared to those working in non-problem buildings (aRR 1.28; 95% CI 0.99-1.64).

DISCUSSION

In our study, poor perceived indoor air was significantly associated with self-reported voice disorders in teachers and there was an agreement between the perceived and technical assessments. Our results also indicated a possible connection between the technical assessment and voice disorders. Our results imply the need for longitudinal research with technical assessment to study the effect of renovation on voice disorders.

The Influence of Ventilation Measures on the Airborne Risk of Infection in Schools: A Scoping Review

OBJECTIVES

To review the risk of airborne infections in schools and evaluate the effect of intervention measures reported in field studies.

BACKGROUND

Schools are part of a country's critical infrastructure. Good infection prevention measures are essential for reducing the risk of infection in schools as much as possible, since these are places where many individuals spend a great deal of time together every weekday in a small area where airborne pathogens can spread quickly. Appropriate ventilation can reduce the indoor concentration of airborne pathogens and reduce the risk of infection.

METHODS

A systematic search of the literature was conducted in the databases Embase, MEDLINE, and ScienceDirect using keywords such as school, classroom, ventilation, carbon dioxide (CO2) concentration, SARS-CoV-2, and airborne transmission. The primary endpoint of the studies selected was the risk of airborne infection or CO2 concentration as a surrogate parameter. Studies were grouped according to the study type.

RESULTS

We identified 30 studies that met the inclusion criteria, six of them intervention studies. When specific ventilation strategies were lacking in schools being investigated, CO2 concentrations were often above the recommended maximum values. Improving ventilation lowered the CO2 concentration, resulting in a lower risk of airborne infections.

CONCLUSIONS

The ventilation in many schools is not adequate to guarantee good indoor air quality. Ventilation is an important measure for reducing the risk of airborne infections in schools. The most important effect is to reduce the time of residence of pathogens in the classrooms.

Ventilation and thermal conditions in secondary schools in the Netherlands: Effects of COVID-19 pandemic control and prevention measures

During the COVID-19 pandemic, the importance of ventilation was widely stressed and new protocols of ventilation were implemented in school buildings worldwide. In the Netherlands, schools were recommended to keep the windows and doors open, and after a national lockdown more stringent measures such as reduction of occupancy were introduced. In this study, the actual effects of such measures on ventilation and thermal conditions were investigated in 31 classrooms of 11 Dutch secondary schools, by monitoring the indoor and outdoor CO2 concentration and air temperature, both before and after the lockdown. Ventilation rates were calculated using the steady-state method. Pre-lockdown, with an average occupancy of 17 students, in 42% of the classrooms the CO2 concentration exceeded the upper limit of the Dutch national guidelines (800 ppm above outdoors), while 13% had a ventilation rate per person (VRp) lower than the minimum requirement (6 l/s/p). Post-lockdown, the indoor CO2 concentration decreased significantly while for ventilation rates significant increase was only found in VRp, mainly caused by the decrease in occupancy (average 10 students). The total ventilation rate per classrooms, mainly induced by opening windows and doors, did not change significantly. Meanwhile, according to the Dutch national guidelines, thermal conditions in the classrooms were not satisfying, both pre- and post-lockdown. While opening windows and doors cannot achieve the required indoor environmental quality at all times, reducing occupancy might not be feasible for immediate implementation. Hence, more controllable and flexible ways for improving indoor air quality and thermal comfort in classrooms are needed.

Variations in classroom ventilation during the COVID-19 pandemic: Insights from monitoring 36 naturally ventilated classrooms in the UK during 2021

Seasonal changes in the measured CO2  levels at four schools are herein presented through a set of indoor air quality metrics that were gathered during the height of the COVID-19 pandemic in the UK. Data from non-intrusive environmental monitoring units were remotely collected throughout 2021 from 36 naturally ventilated classrooms at two primary schools and two secondary schools in England. Measurements were analysed to assess the indoor CO2  concentration and temperature . Relative to UK school air quality guidance, the CO2  levels within classrooms remained relatively low during periods of warmer weather, with elevated CO2  levels being evident during the colder seasons, indicating lower levels of per person ventilation during these colder periods. However, CO2  data from the cold period during the latter part of 2021, imply that the per person classroom ventilation levels were significantly lower than those achieved during a similarly cold weather period during the early part of the year. Given that the classroom architecture and usage remained unchanged, this finding suggests that changes in the ventilation behaviours within the classrooms may have altered, and raises questions as to what may have given rise to such change, in a year when, messaging and public concerns regarding COVID-19 varied within the UK. Significant variations were observed when contrasting data, both between schools, and between classrooms within the same school building; suggesting that work is required to understand and catalogue the existing ventilation provisions and architecture within UK classrooms, and that more work is required to ascertain the effects of classroom ventilation behaviours.

Effects of classroom cleaning on student health: a longitudinal study

BACKGROUND

School districts across the world have been grappling with how to keep their schools open, students healthy, and prevent the spread of viruses in their communities.

OBJECTIVE

The aims of this study included assessing both (1) the effectiveness of enhanced classroom cleaning and disinfecting protocol on surface biocontamination and (2) the associations between surface biocontamination and student absence due to illnesses.

METHODS

Cleaning effectiveness was assessed using quantitative adenosine triphosphate (ATP) measurements during a 10-week study period in a sample of 34 public schools (15,814 students), of a district located in the Western US. The schools were randomly assigned to 17 intervention schools implementing enhanced cleaning and disinfecting protocol and 17 control schools cleaning as usual. General estimating equations (GEEs) were used for modeling associations between ATP levels and weekly aggregates of student absences due to respiratory and gastrointestinal illnesses, which were recorded by the schools according to district wide protocol.

RESULTS

The weekly average ATP levels on logarithmic scale were 5.02 (SD 0.53) and 5.26 (SD 0.48) in the intervention and control schools, respectively, where the difference is statistically significant (p < 0.001). The probability of weekly absence due to gastrointestinal illness was significantly associated with ATP levels (parameter estimate 1.16, 95% CI 1.01-1.34, per unit (log) increase of weekly average ATP), where the model accounts for student level, gender, ethnic group, and socioeconomic status as well as for school level attendance, total absence ratio, and ventilation adequacy in classrooms. Associations were not found between ATP levels and weekly probability of any absence, or absence due to respiratory illness.

SIGNIFICANCE

Enhanced cleaning resulted in a significantly lower level of biocontamination on desktops in the intervention group. In addition, a statistically significant association was established between ATP levels on classroom desks and probability of absence due to gastrointestinal illness.

IMPACT

We found that enhanced cleaning protocol, including bi-weekly cleaning of classroom desks, as well as training of custodians and teachers, monitoring of effectiveness, and feedback, yielded a moderate but statistically significantly lower level of biocontamination on desktops, indicated by quantitative ATP monitoring. Within the range of weekly average desktop ATP levels observed, the probability of reported absence due to gastrointestinal illness is estimated to increase from 0.021 to 0.026. Based on the results, enhanced surface cleaning and monitoring its effectiveness is a possible district, state, or even national level policy to support healthy school environments.

Indoor environmental quality in naturally ventilated schools of a dusty region: Excess health risks and effect of heating and desert dust transport

Indoor air quality (IAQ) is impacted by polluted outdoor air in naturally ventilated schools, especially in places where both anthropogenic and natural sources of ambient air pollution exist. CO₂ , PM_2.5 , PM₁₀ , temperature, relative humidity (RH), and noise were measured in five naturally ventilated primary schools in City of Sanliurfa, in a dusty region of Turkey, Southeast Anatolia. Excess risk levels were estimated for particulate matter. Investigation was conducted through an educational year including two seasons in terms of anthropogenic effect, that is, heating/non-heating, and natural effect, that is, desert dust transport/non-dust transport. The median CO₂ concentration was measured to be >1000 ppm in all seasons/schools. Temperature and RH fell out of the comfort zone in October-December, during which pollutant concentrations were considerably increased, specifically in November, that heating and dust transport periods coincide. The overall mean indoor PM₁₀ and PM_2.5 levels were 58 and 31.8 μg/m³ , respectively. Risk assessment indicate that both short (incidence of asthma symptoms in asthmatic children) and long-term (prevalence of bronchitis) effects are considerable with 10.9 (2.4-19.6)% and 19.5 (2.2-38.8)%, respectively. The findings suggest that mechanical ventilation retrofitting with particle filtration is needed to mitigate potential negative health consequences on children.

Thermal Environment and Thermal Comfort in University Classrooms during the Heating Season

In recent years, there has been increasing concern about the effects of indoor thermal environments on human physical and mental health. This paper aimed to study the current status of the thermal environment and thermal comfort in the classrooms of Northeastern University during the heating season. The indoor thermal environment was analyzed with the use of field measurements, a subjective questionnaire, regression statistics, and the entropy weight method. The results show that personnel population density is an important factor affecting the temperature and relative humidity variations in classrooms. The results also show that the temperature and relative humidity in a lecture state are respectively 4.2 °C and 11.4% higher than those in an idle state. In addition, in university classrooms in Shenyang, the actual thermal neutral temperature is 2.5 °C lower than the predicted value of the Predicted Mean Vote. It was found that increasing indoor relative humidity can effectively improve the overall thermal comfort of subjects. Furthermore, the temperature preference of women was higher than that of men. Therefore, when setting the initial heating temperature, the personnel population density and sufficient indoor relative humidity have been identified as the key factors for improving the thermal environment of the classroom.

A Smart System for the Contactless Measurement of Energy Expenditure

Energy Expenditure (EE) (kcal/day), a key element to guide obesity treatment, is measured from CO2 production, VCO2 (mL/min), and/or O2 consumption, VO2 (mL/min). Current technologies are limited due to the requirement of wearable facial accessories. A novel system, the Smart Pad, which measures EE via VCO2 from a room's ambient CO2 concentration transients was evaluated. Resting EE (REE) and exercise VCO2 measurements were recorded using Smart Pad and a reference instrument to study measurement duration's influence on accuracy. The Smart Pad displayed 90% accuracy (±1 SD) for 14-19 min of REE measurement and for 4.8-7.0 min of exercise, using known room's air exchange rate. Additionally, the Smart Pad was validated measuring subjects with a wide range of body mass indexes (BMI = 18.8 to 31.4 kg/m2), successfully validating the system accuracy across REE's measures of ~1200 to ~3000 kcal/day. Furthermore, high correlation between subjects' VCO2 and λ for CO2 accumulation was observed (p < 0.00001, R = 0.785) in a 14.0 m3 sized room. This finding led to development of a new model for REE measurement from ambient CO2 without λ calibration using a reference instrument. The model correlated in nearly 100% agreement with reference instrument measures (y = 1.06x, R = 0.937) using an independent dataset (N = 56).

Understanding teachers' experiences of ventilation in California K-12 classrooms and implications for supporting safe operation of schools in the wake of the COVID-19 pandemic

Classrooms are often under-ventilated, posing risks for airborne disease transmission as schools have reopened amidst the COVID-19 pandemic. While technical solutions to ensure adequate air exchange are crucial, this research focuses on teachers' perceptions and practices that may also have important implications for achieving a safe classroom environment. We report on a (pre-pandemic) survey of 84 teachers across 11 California schools, exploring their perceptions of environmental quality in relation to monitored indoor environmental quality (IEQ) data from their classrooms. Teachers were not educated regarding mechanical ventilation. Errors in HVAC system installation and programming contributed to misunderstandings (because mechanical ventilation was often not performing as it should) and even occasionally made it possible for teachers to turn off the HVAC fan (to reduce noise). Teachers did not accurately perceive (in)sufficient ventilation; in fact, those in classrooms with poorer ventilation were more satisfied with IEQ, likely due to more temperature fluctuations when ventilation rates were higher combined with occupants' tendency to conflate perceptions of air quality and temperature. We conclude that classroom CO2  monitoring and teacher education are vital to ensure that teachers feel safe in the classroom and empowered to protect the health of themselves and their students.

Ventilation conditions and their influence on thermal comfort in examination classrooms in times of COVID-19. A case study in a Spanish area with Mediterranean climate

Current evidence and recent publications have led to the recognition that aerosol-borne transmission of COVID-19 is possible in indoor areas such as educational centers. A crucial measure to reduce the risk of infection in high occupancy indoors is ventilation. In this global pandemic context of SARS-CoV-2 virus infection, a study has been carried out with the main objective of analyzing the effects of natural ventilation conditions through windows on indoor air quality and thermal comfort during on-site examinations in higher education centers during the winter season, as this implies situations of unusual occupation and the impossibility in many cases of taking breaks or leaving classrooms, as well as the existence of unfavorable outdoor weather conditions in terms of low temperatures. For this purpose, in situ measurements of the environmental variables were taken during different evaluation tests. As the main results of the study, ventilation conditions were generally adequate in all the tests carried out, regardless of the ventilation strategy used, with average CO₂ concentration levels of between 450 and 670 ppm. The maximum CO₂ concentration value recorded in one of the tests was 808 ppm. On this basis, the limit for category IDA 2 buildings, corresponding to educational establishments, was not exceeded in any case. However, these measures affected the thermal comfort of the occupants, especially when the outside temperature was below 6 °C, with a dissatisfaction rate of between 25 and 72%. Examinations carried out with outside temperatures above 12 °C were conducted in acceptable comfort conditions regardless of outside air supply and classroom occupancy. In these cases, the dissatisfaction rate was less than 10%. The results obtained have made it possible to establish strategies for ventilation in the implementation of future exams, depending on the climatic conditions outside.

Indoor air quality in the primary school of China-results from CIEHS 2018 study

Indoor air quality ((IAQ) in classrooms was associated with the daily exposure of school-age children who are particularly vulnerable to air pollutants exposure, while few data exist to evaluate classroom indoor air quality nationwide in China. The subsample of the CIEHS 2018 study was performed in 66 classrooms of 22 primary schools nationwide in China. Temperature, relative humidity, PM_2.5, PM₁₀, CO₂, CO, formaldehyde concentrations, bacteria and fungi were detected in all classrooms by using the instruments that meet the specified accuracy. The ratios of indoor to outdoor (I/O) of PM_2.5 were calculated in each classroom to identify whether the indoor environment the pollutants comes from outdoors. The indoor PM_2.5, PM₁₀, CO, HCHO, bacteria and fungi GM concentration are 47.40 μg/m³, 72.91 μg/m³, 0.37 mg/m³, 0.02 mg/m³, 347.51 CFU/m³ and 362.76 CFU/m³, respectively. We observed that there were 66.5%, 52.6%, 22.4%, 1.8%, and 9.6% of the classrooms that exceeded the guideline values of PM_2.5, PM₁₀, CO₂, HCHO, and bacteria, respectively. It should be attention that all of the classroom's PM_2.5 concentrations in Shijiazhuang and Nanning, PM₁₀ concentrations in Nanning, CO₂ concentration in Lanzhou were exceeded the suggested values. Bacteria contamination in Shijiazhuang's classrooms is also serious. All classroom CO concentrations meet the requirement. The results indicated that classroom indoor PM_2.5 was significantly positively correlated with indoor PM₁₀ and CO₂, while was negative correlated with temperature, CO, and fungi. Our results suggest that indoor air pollution in classrooms was a severe problem in Chinese primary schools. It is necessary to strengthen ventilation in the classroom to improve indoor air quality. What's more, a healthy learning environment should be created for primary school students.

Indoor Air Quality Prior to and Following School Building Renovation in a Mid-Atlantic School District

Children spend the majority of their time indoors, and a substantial portion of this time in the school environment. Air pollution has been shown to adversely impact lung development and has effects that extend beyond respiratory health. The goal of this study was to evaluate the indoor environment in public schools in the context of an ongoing urban renovation program to investigate the impact of school building renovation and replacement on indoor air quality. Indoor air quality (CO₂, PM_2.5, CO, and temperature) was assessed for two weeks during fall, winter, and spring seasons in 29 urban public schools between December 2015 and March 2020. Seven schools had pre- and post-renovation data available. Linear mixed models were used to examine changes in air quality outcomes by renovation status in the seven schools with pre- and post-renovation data. Prior to renovation, indoor CO measurements were within World Health Organization (WHO) guidelines, and indoor PM_2.5 measurements rarely exceeded them. Within the seven schools with pre- and post-renovation data, over 30% of indoor CO₂ measurements and over 50% of indoor temperatures exceeded recommended guidelines from the American Society of Heating, Refrigerating, and Air Conditioning Engineers. Following renovation, 10% of indoor CO₂ measurements and 28% of indoor temperatures fell outside of the recommended ranges. Linear mixed models showed significant improvement in CO₂, indoor PM_2.5, and CO following school renovation. Even among schools that generally met recommendations on key guidelines, school renovation improved the indoor air quality. Our findings suggest that school renovation may benefit communities of children, particularly those in low-income areas with aging school infrastructure, through improvements in the indoor environment.

Identifying the K-12 classrooms' indoor air quality factors that affect student academic performance

The objective of this study was to investigate associations between indoor air quality (IAQ) in K-12 classrooms and student academic performance. During the academic years 2015-2017, various IAQ factors in 220 classrooms in the US were measured seasonally, excluding summer. Measurements were taken during occupied and unoccupied times in several classrooms within each school. Occupied measurements included indoor carbon dioxide (CO₂) and formaldehyde concentrations, and fine and coarse particle counts. Unoccupied measurements consisted of ozone (O₃), carbon monoxide (CO), nitrogen dioxide (NO₂), and total volatile organic compounds (TVOCs) concentrations. Ventilation rates of classrooms were estimated using measured CO₂ concentrations. In addition to IAQ data, classroom aggregated student achievement scores and demographic information were collected from participating school districts. Demographic data included percentage rates of free and reduced lunch recipients (PFRL), high-performance students (PGIF), and special education students (PSPED). A multivariate linear regression analysis was used to investigate the associations between IAQ factors and student scores using demographic data as controls. The results revealed associations between student scores and ventilation system type, ventilation rates, fine particle counts, and O₃ and CO concentrations. This research provides valuable information to school districts and design engineers, enabling them to design school environments for improved student performance.

The importance of servicescapes in Maldivian higher education: application of the stimuli-organism-response(SOR) framework

Purpose

This study aims to use the servicescape model of higher education environments to measure the students’ perceptions of the learning environment (classroom) and the effect this has on students’ learning ability.

Design/methodology/approach

The present study follows the stimulus-organism-response paradigm framework. A self-administered and well-structured survey questionnaire is used to collect data. The snowball sampling technique is used to collect samples of 403 students belonging to Maldivian higher education institutions.

Findings

Findings show that the physical appearances of these higher education institutions greatly influenced the pleasure dimension. Furthermore, pleasure is found to have a significant and positive relationship with the approach behaviour and engagement/involvement of the students.

Originality/value

The main contribution of the study is that it successfully tests the “Eduscape” model adopted from the servicescape model, and thus helps to extend existing knowledge on the critical elements in the Maldivian higher education learning environments and student’s behaviour within them. The findings have implications for higher education institutions to improve their learning environments and better engage with their students.

Indoor Climate Performance in a Renovated School Building

Indoor climate comfort is important for school buildings. Nowadays, this is a topical problem, especially in renovated buildings. Poorly ventilated school classrooms create improper conditions for classrooms. A post-occupancy study was performed in a school building in temperate climatic conditions. The evaluation was based on the results of long-term monitoring of the natural ventilation strategy and measurements of the carbon dioxide concentration in the school classroom’s indoor environment. The monitoring was carried out in an old school building that was constructed in the 1970s and compared to testing carried out in the same school classroom after the building was renovated in 2016. Surprisingly, the renovated classroom had a significantly higher concentration of CO2. It was found that this was due to the regulation of the heating system and the new airtight windows. The occupants of the renovated classroom have a maintained thermal comfort, but natural ventilation is rather neglected. A controlled ventilation strategy and installation of heat recovery units are recommended to solve these problems with the classroom’s indoor environment. Microbiological testing of the surfaces in school classrooms also shows the importance of fresh air and solar radiation access for indoor comfort.

Human responses to high levels of carbon dioxide and air temperature

In this study, 30 subjects were exposed to different combinations of air temperature (T_a : 24, 27, and 30°C) and CO₂ level (8000, 10 000, and 12 000 ppm) in a high-humidity (RH: 85%) underground climate chamber. Subjective assessments, physiological responses, and cognitive performance were investigated. The results showed that as compared with exposure to T_a  = 24°C, exposure to 30°C at all CO₂ levels caused subjects to feel uncomfortably warm and experience stronger odor intensity, while increased mental effort and greater intensity of acute health symptoms were reported. However, no significant effects of T_a on task performance or physiological responses were found. This indicated that subjects had to exert more effort to maintain their performance in an uncomfortably warm environment. Increasing CO₂ from 8000 to 12 000 ppm at all T_a caused subjects to report higher rates of headache, fatigue, agitation, and feeling depressed, although the results were statistically significant only at 24 and 27°C. The text typing performance and systolic blood pressure (SBP) decreased significantly at this exposure, whereas diastolic blood pressure (DBP) and thermal discomfort increased significantly. These effects suggest higher arousal/stress. No significant interaction effect of T_a and CO₂ concentration on human responses was identified.

From spontaneous to strategic natural window ventilation: Improving indoor air quality in Swiss schools

Natural window ventilation is frequently employed in schools in Europe and often leads to inadequate levels of human bioeffluents. However, intervention studies that verify whether recommended ventilation targets can be achieved in practice with reasonable ventilation regimes and that are also suitable for countries with cold winters are practically non-existent. To explore the initial situation in Switzerland we carried out carbon dioxide (CO₂) measurements during the winter in 100 classrooms, most of which (94%) had natural window ventilation. In more than two thirds of those, the hygienic limit value of 2000 ppm specified for CO₂ in the Swiss Standard SN 520180 (2014) was exceeded. To improve ventilation behavior, an intervention was implemented in 23 classrooms during the heating season. Ventilation was performed exclusively during breaks (to avoid discomfort from cold and drafts), efficiently, and only for as long as was necessary to achieve the ventilation objective of compliance with the hygienic limit value (strategic ventilation). The intervention included verbal and written instructions, awareness-raising via a school lesson and an interactive tool for students, which was also used to estimate the required duration of ventilation. CO₂ exposure was significantly reduced in pilot classes (Wilcoxon signed-rank test, p = 3.815e^-06). Median CO₂ levels decreased from 1600 ppm (control group) to 1097 ppm (intervention group), and the average proportion of teaching time at 400-1400 ppm CO₂ increased from 40% to 70%. The duration of ventilation was similar to spontaneous natural window ventilation (+5.8%). Stricter ventilation targets are possible. The concept of the intervention is suitable for immediate adoption in schools with natural window ventilation for a limited period, pending the installation of a mechanical ventilation system. The easy integration of this intervention into everyday school life promotes compliance, which is particularly important during the COVID-19 pandemic.

Assessment of Indoor Air Parameters in Building Equipped with Decentralised Façade Ventilation Device

The study contains an analysis of a decentralised unit installed in a building façade, where air supply and exhaust cycles are swapped by proper positioning of dampers. The analysis was carried out in real conditions in an office building. The Computational Fluid Dynamics (CFD) simulation is an important element of the system design, and has become more and more widely used. Simulation of the analysed unit has shown air stream distribution in a room. Moreover, it allowed for determination of indoor air temperature. Completed analysis and CFD simulations allow for the observation that façade ventilation systems provide a good way to improve the indoor microclimate, as they effectively reduce air pollution. The decentralised façade ventilation unit reduced the carbon dioxide concentration to a level lower than 1000 ppm and maintained the indoor air temperature in the range of 19.5–22 °C. The error for CFD simulation equals 0.5%, which is not much. The results of research and analysis show that the highest reduction of carbon dioxide concentration occurred when supply/exhaust time equalled 10 min. At the same time, when supply/exhaust time equalled 10 min, the indoor air temperature was the lowest of the recorded values.

Review of IAQ in Premises Equipped with Façade–Ventilation Systems

Poor indoor air quality affects the health of the occupants of a given structure or building. It reduces the effectiveness of learning and work efficiency. Among many pollutants, PM 2.5 and 10 dusts are extremely important. They can be eliminated using mechanical ventilation equipped with filters. Façade ventilation devices are used as a way to improve indoor air quality (IAQ) in existing buildings. For their analysis, researchers used carbon dioxide as a tracer gas. They have shown that façade ventilation devices are an effective way to improve IAQ, but require further analysis due to the sensitivity of façade ventilation devices to the effects of wind and outdoor temperature. In addition, legal regulations in some countries require verification in order to enable the use of this type of solution as a way to improve IAQ in an era characterised by the effort to transform buildings into passive houses (standard for energy efficiency in a building).

Investing in a better future: higher education and post-COVID Canada

Post-secondary education (PSE) is a vital part of civil society and any modern economy. When broadly accessible, it can enable socioeconomic mobility, improve health outcomes, advance social cohesion, and support a highly skilled workforce. It yields public benefits not only in improved well-being and economic prosperity, but also in reduced costs in health care and social services. Canada also relies heavily on the PSE sector for research. During the COVID-19 pandemic, PSE has supported research related to the pandemic response and other critical areas, including providing expert advice to support public health and government decision-making, while maintaining educational programs and continuing to contribute to local and regional economies. But the pandemic effort has stretched already strained PSE resources and people even further: for decades, declining public investment has driven increases in tuition and decreases in faculty complement, undermining Canada’s research capacity and increasing student debt as well as destabilizing the sector through a growing reliance on volatile international education markets. Given the challenges before us, including climate change, reconciliation, and the pandemic, it is imperative that we better draw on the full range of experience, knowledge, and creativity in Canada and beyond through an inclusive, stable, and globally engaged PSE. Supporting PSE’s recovery will be key to Canada’s ongoing pandemic response and recovery. The recommendations in this report are guided by a single goal—to make the post-secondary sector a more effective partner and support in building a more equitable, sustainable, and evidence-driven future for Canada, through and beyond the COVID-19 pandemic.

Research on the effect of different position on classroom ventilation in a “L” type teaching building

The ventilation effect in different places in the teaching building is different. The aim of this paper is to study the relative ventilation relationship of the rooms in “L” type middle school teaching building. Taking Xiamen in the subtropical region as a typical city, different aspect ratio for 1:1, 1:1.5 and 1:2 were set as variables, using the CFD simulation method. Combined and separated effects of the defined parameters on natural ventilation performance are evaluated using the ratio of age of air area as criteria. The result shows that the “L” type teaching building ventilated condition presents several characteristics as the approaching wind direction changed. Corner, long wing and short wing of building have some influences on the wind environment for classrooms. In addition, different aspect ratio “L” type buildings correspond to different optimal inlet wind angles. The research results in this paper can help architects to design buildings more scientifically and reasonably.

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Ventilation performance in different position classrooms are different.

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The best inlet wind direction locates in the range of 120^。 to 150^。For 1:1 L type building.

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The best wind angles for classroom ventilation of “1:1.5” type teaching building is from 330° to 60°.

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The best inlet wind angles for classroom ventilation of “1:2” type teaching building is from 90° to 240°.

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For LW side, the closer to inlet wind, the bigger wind pressure of classroom in directions 0°–60°, 120°–180°, 270°–360°.

Indoor CO2 concentrations and cognitive function: A critical review

Poor indoor air quality indicated by elevated indoor CO₂ concentrations has been linked with impaired cognitive function, yet current findings of the cognitive impact of CO₂ are inconsistent. This review summarizes the results from 37 experimental studies that conducted objective cognitive tests with manipulated CO₂ concentrations, either through adding pure CO₂ or adjusting ventilation rates (the latter also affects other indoor pollutants). Studies with varied designs suggested that both approaches can affect multiple cognitive functions. In a subset of studies that meet objective criteria for strength and consistency, pure CO₂ at a concentration common in indoor environments was only found to affect high-level decision-making measured by the Strategic Management Simulation battery in non-specialized populations, while lower ventilation and accumulation of indoor pollutants, including CO₂ , could reduce the speed of various functions but leave accuracy unaffected. Major confounding factors include variations in cognitive assessment methods, study designs, individual and populational differences in subjects, and uncertainties in exposure doses. Accordingly, future research is suggested to adopt direct air delivery for precise control of CO₂ inhalation, include brain imaging techniques to better understand the underlying mechanisms that link CO₂ and cognitive function, and explore the potential interaction between CO₂ and other environmental stimuli.

Simulation study for natural ventilation retrofitting techniques in educational classrooms - A case study

Building retrofitting plays a critical role in achieving sustainable development and is an efficient way to improve the indoor air quality (IAQ) of existing spaces. The IAQ in classrooms has a significant impact on the health and academic achievement of students. However, improving the IAQ of existing classrooms is challenging if minimum architectural modifications are allowed. Different natural ventilation retrofitting techniques were proposed to improve the IAQ in existing classrooms at Jordan University of Science and Technology, which is located in a hot arid region. Computer simulations were used to analyze the ventilation rate, indoor operative temperature, relative humidity, and CO₂ concentration in the base Case classroom and after the implementation of the proposed retrofitting techniques. Simulation results were compared with those obtained in the base case to determine the most efficient natural ventilation retrofitting technique. The best results were obtained by using a solar chimney to assist a wind tower, which resulted in an increase in the comfort hours during the occupation time, an improvement in the average monthly ventilation rate range, a decrease in the CO2 concentration, and an improvement in the relative humidity ratio. An energy-saving of 39% would be achieved compared with the use of split unit air condition systems. Economic assessment of the proposed system using net present value indicates positive economic viability.

Microclimate in Rooms Equipped with Decentralized Façade Ventilation Device

Many building are characterized by insufficient air exchange, which may result in the symptoms of sick building syndrome (SBS). A large number of existing buildings are equipped with natural ventilation, whose work is disturbed by activities going to energy-saving. The thermomodernization activities are about mounting new sealed windows and laying thermal isolation, which reduces the amount of infiltrating/exfiltrating air. In many cases, the mechanical ventilation cannot be used due to a lack of a place in building or architectural and construction requirements. One of the solutions to improve the indoor microclimate is the decentralized façade ventilation. In the article, the internal air parameters in an office room equipped with decentralized façade ventilation device were analyzed. The room was equipped with a decentralized façade unit, which cyclically supplied and removed air from the room. The time of the supply/exhaust was changed to 2 min, 4 min, and 10 min. The temperature and the humidity of the indoor air and the outdoor air and the concentration of carbon dioxide inside the room were measured. The analysis showed that despite the lack of a heater in the device, the air temperature in the workplace and in the central point of the room was in the range of 20–22 °C. The air humidity was in the range of 27–43%.

Indoor air quality at school and students' performance: Recommendations of the UNESCO Chair on Health Education and Sustainable Development & the Italian Society of Environmental Medicine (SIMA)

The issue of indoor air quality (IAQ) concerns 64 million students across Europe, but it is still a neglected topic, although it impacts both their health and learning outcomes. Classroommicroclimate is the first key factor determining a healthy or unhealthy school environment, and it is influenced by ventilation, temperature and humidity rate. Classrooms are usually crowded, overheated and poorly ventilated, thus resulting in possible increases of carbon dioxide (CO₂), that can cause several problems when its concentrations exceed the value of 0.15 percentage volume of CO₂ (1500 ppm) or even at lower levels (1000 ppm). CO₂ can also arise from outside the school, being widely produced by the combustion of fossils or road traffic. Anthropogenic activities are responsible for the emission of nitrogen dioxide (NO₂) and polycyclic aromatic hydrocarbons(PAH) too, which represent other possible external contaminants potentially impairing IAQ. Furtherdangerous exposures for students' health are those related to natural emission of gas Radon, which typically accumulates in poorly ventilated classrooms, and volatile organic compounds (VOCs, released by building materials, paints, furnishings, detergents), while chemicals substances (i.e.cyanoacrylate, lead, cadmium, nickel) might be contained in school materials. Finally, particulate matter (PM2.5 and PM10) originating from road traffic, domestic heating or industrial activities represent additional possible contaminants impacting schools' air quality. Poor IAQ might result in mild adverse events (i.e. headaches, nausea etc.) or cause respiratory problems. More frequently, IAQ affects students' attention and their school performances, as widely documented by many studies. Standardized tests administered to pupils exposed to poor IAQ (to assess reading and mathematical abilities) systematically result in worse outcomes compared to students staying in healthy classroom environments. In this paper, we present recommendations of UNESCO Chair on Health Education and Sustainable Development and Italian Society of Environmental Medicine(SIMA) to ensure an optimal IAQ at school, including some post-COVID-19 issues.

Does energy efficiency-indoor air quality dilemma have an impact on the gross domestic product?

Increased energy efficiency of the building stock is one of the main tools to reduce climate change. Improved airtightness of the building envelope has a side effect - the need for higher ventilation rates which, in turn, lead to a higher energy bill and reduced indoor air quality. This creates an energy efficiency - indoor air quality dilemma. This study evaluates the dilemma impact on the gross domestic product (GDP). System dynamics modelling is applied to answer this question. The education system and labour market of Latvia is used as the case study. Simulation results show that even if all education buildings in Latvia have improved energy efficiency performance and have a significant reduction of outdoor CO₂ level, indoor CO₂ is very high if no mechanical ventilation is used. The best solution is to increase energy efficiency while providing good indoor air quality by operating mechanical ventilation since the increase in GDP provides financial sources for further energy efficiency measures.

Potted plants do not improve indoor air quality: a review and analysis of reported VOC removal efficiencies

Potted plants have demonstrated abilities to remove airborne volatile organic compounds (VOC) in small, sealed chambers over timescales of many hours or days. Claims have subsequently been made suggesting that potted plants may reduce indoor VOC concentrations. These potted plant chamber studies reported outcomes using various metrics, often not directly applicable to contextualizing plants' impacts on indoor VOC loads. To assess potential impacts, 12 published studies of chamber experiments were reviewed, and 196 experimental results were translated into clean air delivery rates (CADR, m³/h), which is an air cleaner metric that can be normalized by volume to parameterize first-order loss indoors. The distribution of single-plant CADR spanned orders of magnitude, with a median of 0.023 m³/h, necessitating the placement of 10-1000 plants/m² of a building's floor space for the combined VOC-removing ability by potted plants to achieve the same removal rate that outdoor-to-indoor air exchange already provides in typical buildings (~1 h^-1). Future experiments should shift the focus from potted plants' (in)abilities to passively clean indoor air, and instead investigate VOC uptake mechanisms, alternative biofiltration technologies, biophilic productivity and well-being benefits, or negative impacts of other plant-sourced emissions, which must be assessed by rigorous field work accounting for important indoor processes.

IEQ Field Investigation in High-Performance, Urban Elementary Schools

School buildings are one of the most commonly occupied building types for children, second only to their homes. Indoor environmental quality (IEQ) is an ongoing issue in schools, especially in urban environments where students are exposed to higher levels of outdoor pollutants. To examine this issue, five elementary school buildings located in a major city on the East Coast of the United States were selected for one-week of quantitative IEQ measurements, with a satisfaction survey collected from teachers at the selected schools. The schools included three high-performance schools, one recently renovated school, and one conventional school. Despite building designers and operators following the recommendations of current high-performance design standards, the three high-performance school buildings did not have measurably better IEQ than the renovated and conventional school buildings, nor were they perceived as better based on the satisfaction survey. This indicates that current high-performance design standards may not place enough emphasis on reducing health-related pollutants in urban schools.

Indoor carbon dioxide concentrations in Croatian elementary school classrooms during the heating season

Aware that exposure to stuffy indoor air with high levels of carbon dioxide (CO2) is associated with higher absenteeism and reduced academic performance in school pupils, the World Health Organization (WHO) Regional Office for Europe initiated indoor air quality surveys in schools, including CO2 monitoring, to assess ventilation and exposure to stuffy air. Here we report the findings of the first such survey in Croatia. It was conducted in 60 classrooms of 20 urban and rural elementary schools throughout the country during the heating season. Measurements of CO2 levels showed that all 60 classrooms exceeded the international guidelines of 1938 mg/m3. Mean CO2 concentrations ranged from 2771 to 7763 mg/m3. The highest concentration measured in urban schools was 7763 mg/m3 and in rural schools 4771 mg/m3. Average CO2 levels were higher in continental schools (3683 mg/m3) than the coastal ones (3134 mg/m3), but all demonstrate poor ventilation during the heating season all over Croatia.

Indoor Environmental Quality Evaluation of Lecture Classrooms in an Institutional Building in a Cold Climate

In this paper, ventilation, indoor air quality (IAQ), thermal and acoustic conditions, and lighting were studied to evaluate the indoor environmental quality (IEQ) in an institutional building at the University of Alberta in Edmonton, Canada. This study examined IEQ parameters, including pressure, illuminance, acoustics, carbon dioxide (CO2) concentration, temperature, and humidity, with appropriate monitors allocated during a lecture (duration 50 min or 80 min) in four lecture classrooms repeatedly (N = 99) from October 2018 to March 2019 with the objectives of providing a comprehensive analysis of interactions between IEQ parameters. The classroom environments were maintained at 23 ± 1 °C and 33% ± 3% RH during two-season measurements. Indoor mean CO2 concentrations were 550–1055 ppm, and a mean sound level of 58 ± 3 dBA was observed. The air change rates were configured at 1.3–6.5 per hour based on continuous CO2 measurements and occupant loads in the lectures. A variance analysis indicated that the within-lecture classroom variations in most IEQ parameters exceeded between-lecture classrooms. A multilayer artificial neural network (ANN) model was developed on the basis of feedforward networks with a backpropagation algorithm. ANN results demonstrated the importance of the sequence of covariates on indoor conditions (temperature, RH, and CO2 level): Air change rate (ACR) > room operations (occupant number and light system) > outdoor conditions.

Building and indoor environmental quality assessment of Nigerian primary schools: A pilot study

A total of 15 classrooms went through on-site assessments/inspections, including measurements of temperature (T), and concentrations of carbon monoxide (CO) and carbon dioxide (CO₂ ). In addition, the level of surface biocontamination/cleaning effectiveness was assessed by measuring adenosine triphosphate (ATP) levels on students' desks. Based on the data, the quality of facilities in the buildings was low. Classroom occupancy exceeded ASHRAE 50 person/100 m² standard in all cases indicating overcrowding. However, concentrations of CO₂ remained below 1000 ppm in most classrooms. On the other hand, indoor T was above the recommended levels for thermal comfort in all classrooms. Maximum indoor CO was 6 ppm. Median ATP concentrations on the desk tops were moderately high in all schools. The use of open incinerators and power generator sets near classrooms, which was suspected to be the main source of CO, should be discouraged. Improved hygiene could be achieved by providing the students access to functioning bathroom facilities and cafeteria, and by effective cleaning of high contact surfaces such as desks. Although ventilation seems adequate based on CO₂ concentrations, thermal comfort was not attained especially in the afternoon during extreme sunlight. Therefore, installing passive and/or mechanical cooling systems should be considered in this regard.

Investigation and Evaluation of Winter Indoor Air Quality of Primary Schools in Severe Cold Weather Areas of China

The indoor air quality (IAQ) in classrooms has attracted more and more attention. Unfortunately, there is limited information relating to IAQ in the primary schools in severe cold weather areas of China. In this study, a field investigation on the IAQ of a primary school of Shenyang in northeast China was carried out by physical measurements and questionnaire surveys. The carbon dioxide (CO2) concentration in selected classrooms was continuously measured for a week, and the corresponding ventilation rate was calculated. Meanwhile, the perceptions of the IAQ, the purpose and the comfort degree of window opening have also been recorded from 106 pupils, aged 9–12. The results indicate the ventilation rate is considerably inadequate in about 99% of the class time due to the low frequency of window opening. The average daily CO2 concentration in these classrooms is 1510–3863 ppm, which is far higher than the recommended value of 1000 ppm. Most pupils understand that the purpose of opening windows in winter is to improve air quality. However, there are big differences between the measurement results and subjective judgments of indoor air quality. Contrary to the high measured CO2 concentration, around 70% pupils consider the air fresh, and only 3.7% pupils are dissatisfied and even very dissatisfied with IAQ in their classroom. It is necessary to change the existing manual window opening mode, because the pupils’ subjective judgment affects the window opening behavior.

Indoor air quality in schools of a highly polluted south Mediterranean area

This study aimed at surveying lower secondary schools in southern Italy, in a highly polluted area. A community close to an industrial area and three villages in rural areas was investigated. Indoor temperature, relative humidity (RH), gaseous pollutants (CO₂ and NO₂ ), selected biological pollutants in indoor dust, and the indoor/outdoor mass concentration and elemental composition of PM_2.5 were ascertained. Temperature and RH were within, or close to, the comfort range, while CO₂ frequently exceeded the threshold of 1000 ppm, indicating inadequate air exchange rate. In all the classrooms, median NO₂ levels were above the WHO threshold value. Dermatophagoides p. allergen concentration was below the sensitizing threshold, while high endotoxin levels were detected in the classrooms, suggesting schools may produce significant risks of endotoxin exposure. Concentration and solubility of PM_2.5 elements were used to identify the sources of indoor particles. Indoor concentration of most elements was higher than outdoors. Resuspension was responsible for the indoor increase in soil components. For elements from industrial emission (Cd, Co, Ni, Pb, Sb, Tl, V), the indoor concentration depended on penetration from the outside. For these elements, differences in rural vs industrial concentrations were found, suggesting industrial sources may influence indoor air quality nearby schools.

Online Questionnaire as a Tool to Assess Symptoms and Perceived Indoor Air Quality in a School Environment

School environments are a complex entirety where various different exposure factors are related that contribute to the indoor air quality (IAQ) and may affect occupants’ health and well-being. Indoor air questionnaires are useful for collecting information about the occupants’ experiences and perceptions of the indoor air and for evaluating the results of the measures taken. A common way to implement health questionnaires is to ask the respondents to describe symptoms at certain time points, such as weeks or months. The aim of our study was to develop a short and easy online questionnaire to assess symptoms and perceived IAQ. We also aimed to test the usability of the questionnaire in school buildings and assess the differences between the online measurement data (CO2, T, and RH) and the IAQ complaints and symptoms reported by the pupils. A total of 105 teachers and 1268 pupils in 36 classrooms at six schools answered the questionnaires over a two-week period. The participants completed the questionnaire always after the lesson in the studied classroom. We received 719 answers from the teachers and 6322 answers from the pupils. The results demonstrated that the teachers reported more IAQ problems and symptoms than the pupils did. Differences between classrooms were observed in both the IAQ problem and reference schools. The most common significant differences (p-value > 0.05) between the classrooms were among humidity, too cold air, and stuffy air, and among symptoms, dry/sore throat, tiredness, headache, and skin symptoms. Maximum values of CO2 measurements and the highest prevalence of stuffy air were relatively consistent. The testing process demonstrated that such a questionnaire was suitable for adults and children aged at least 12 years. The results of our study suggest that a quick and easy online questionnaire that is completed within a short period may be useful for gathering valuable knowledge about perceived IAQ. It could be used in combination with other indoor environment investigations to produce detailed results and restorative measures.

Outcome-based ventilation: A framework for assessing performance, health, and energy impacts to inform office building ventilation decisions

This article presents an outcome-based ventilation (OBV) framework, which combines competing ventilation impacts into a monetized loss function ($/occ/h) used to inform ventilation rate decisions. The OBV framework, developed for U.S. offices, considers six outcomes of increasing ventilation: profitable outcomes realized from improvements in occupant work performance and sick leave absenteeism; health outcomes from occupant exposure to outdoor fine particles and ozone; and energy outcomes from electricity and natural gas usage. We used the literature to set low, medium, and high reference values for OBV loss function parameters, and evaluated the framework and outcome-based ventilation rates using a simulated U.S. office stock dataset and a case study in New York City. With parameters for all outcomes set at medium values derived from literature-based central estimates, higher ventilation rates' profitable benefits dominated negative health and energy impacts, and the OBV framework suggested ventilation should be ≥45 L/s/occ, much higher than the baseline ~8.5 L/s/occ rate prescribed by ASHRAE 62.1. Only when combining very low parameter estimates for profitable impacts with very high ones for health and energy impacts were all outcomes on the same order. Even then, however, outcome-based ventilation rates were often twice the baseline rate or more.

Building Evidence for Health: Green Buildings, Current Science, and Future Challenges

Civilizational challenges have questioned the status quo of energy and material consumption by humans. From the built environment perspective, a response to these challenges was the creation of green buildings. Although the revolutionary capacity of the green building movement has elevated the expectations of new commercial construction, its rate of implementation has secluded the majority of the population from its benefits. Beyond reductions in energy usage and increases in market value, the main strength of green buildings may be the procurement of healthier building environments. Further pursuing the right to healthy indoor environments could help the green building movement to attain its full potential as a transformational public health tool. On the basis of 40 years of research on indoor environmental quality, we present a summary of nine environment elements that are foundational to human health. We posit the role of green buildings as a critical research platform within a novel sustainability framework based on social-environmental capital assets.

The ventilation problem in schools: literature review

Based on a review of literature published in refereed archival journals, ventilation rates in classrooms often fall far short of the minimum ventilation rates specified in standards. There is compelling evidence, from both cross-sectional and intervention studies, of an association of increased student performance with increased ventilation rates. There is evidence that reduced respiratory health effects and reduced student absence are associated with increased ventilation rates. Increasing ventilation rates in schools imposes energy costs and can increase heating, ventilating, and air-conditioning system capital costs. The net annual costs, ranging from a few dollars to about 10 dollars per person, are less than 0.1% of typical public spending on elementary and secondary education in the United States. Such expenditures seem like a small price to pay given the evidence of health and performance benefits.

The effect of low ventilation rate with elevated bioeffluent concentration on work performance, perceived indoor air quality, and health symptoms

The aim of this laboratory experiment was to study the effects of ventilation rate, and related changes in air quality, predominantly bioeffluents, on work performance, perceived indoor air quality, and health symptoms in a typical conditions of modern open-plan office with low material and equipment emissions. In Condition A, outdoor air flow rate of 28.2 l/s person (CO₂ level 540 ppm) was applied and in Condition B, outdoor air flow rate was 2.3 l/s person (CO₂ level 2260 ppm). CO₂ concentration level was used as an indicator of bioeffluents. Performance was measured with seven different tasks which measure different cognitive processes. Thirty-six subjects participated in the experiment. The exposure time was 4 hours. Condition B had a weak negative effect on performance only in the information retrieval tasks. Condition B increased slightly subjective workload and perceived fatigue. No effects on health symptoms were found. The intensity of symptoms was low in both conditions. The experimental condition had an effect on perceived air quality and observed odor intensity only in the beginning of the session. Although the room temperature was controlled in both conditions, the heat was perceived to impair the performance more in Condition B.

Ventilation rates in recently constructed U.S. school classrooms

Low ventilation rates (VRs) in schools have been associated with absenteeism, poorer academic performance, and teacher dissatisfaction. We measured VRs in 37 recently constructed or renovated and mechanically ventilated U.S. schools, including LEED and EnergyStar-certified buildings, using CO₂ and the steady-state, build-up, decay, and transient mass balance methods. The transient mass balance method better matched conditions (specifically, changes in occupancy) and minimized biases seen in the other methods. During the school day, air change rates (ACRs) averaged 2.0±1.3 hour^-1 , and only 22% of classrooms met recommended minimum ventilation rates. HVAC systems were shut off at the school day close, and ACRs dropped to 0.21±0.19 hour^-1 . VRs did not differ by building type, although cost-cutting and comfort measures resulted in low VRs and potentially impaired IAQ. VRs were lower in schools that used unit ventilators or radiant heating, in smaller schools and in larger classrooms. The steady-state, build-up, and decay methods had significant limitations and biases, showing the need to confirm that these methods are appropriate. Findings highlight the need to increase VRs and to ensure that energy saving and comfort measures do not compromise ventilation and IAQ.