Classroom Air Research Articles

Gene-environment interaction between an IL4R variant and school endotoxin exposure contributes to asthma symptoms in inner-city children

Gene-environment interaction between an IL4R variant and school endotoxin exposure contributes to asthma symptoms in inner-city children

Current asthma, respiratory symptoms and airway infections among students in relation to the school and home environment in Japan

ABSTRACTObjective: To study associations between the school and home environment and current asthma, respiratory symptoms and airway infections among Japanese students. Methods: Japanese students (12–15 y) (N = 1048) in four schools responded to a questionnaire on respiratory health, allergy and the home environment. Temperature, relative air humidity (RH) and student density (students/m2 floor area) was measured in the classrooms: dust was collected from floors and in classroom air and analysed for cat (Fel d 1) and dog (Can f 1) allergens. Health associations were analysed by multi-level logistic regression. Results: Doctor's diagnosed asthma was common (13.4%), 8.8% reported cat allergy and 6.1% dog allergy. The median level in floor dust was 41 ng/g (IQR 23–92) for Fel d 1 and 101 ng/g (IQR 54–101) for Can f 1. The median level in air was 18.6 ng/ m2/ day (IQR5.9–25.1) for Fel d 1 and 18.6 ng/ m2/ day (IQR 6.0–13.3) for Can f 1. High RH, high student density and airborne cat allergen was associated with airway infections. In the home environment, recent indoor painting, new floor materials, odour, having cats as pets, window pane condensation in winter, and dampness in floor construction were associated with respiratory illness. Conclusion: High relative air humidity, high student density and airborne cat allergens at school may increase the risk of airway infections. Having cats as pets, chemical emissions from paint and new floor materials, odour and dampness can constitute domestic risk factors for respiratory symptoms while having dogs as pets could be protective.

Ability to Determine the Quality of Indoor Air in Classrooms without Sensors

The search for new possibilities for assessing indoor air quality is one of the major challenges of our times. Results of many present investigations organized around the world indicates, that we are still not able to cope with inadequate air quality in many types of building. This fact results in a deterioration of occupants comfort and in the long time damage to health. For this reason indoor air quality in educational institutions deserves special attention. Children are more sensitive to contamination of indoor air and their ability to concentrate is dependent on the state of the air in the room, which affect later examination results. Considering the fact, that classrooms are used in a schematic way, in this paper it is proposed to use currently available calculation formula for determining the concertation of carbon dioxide, which is an indicator of indoor air quality. Results of calculations were compared with measurement data of carbon dioxide concertation collected in classrooms with natural ventilation. With appropriate data and assumptions calculation formula allow to determine the quality of indoor air in classrooms.

School Environmental Intervention to Reduce Particulate Pollutant Exposures for Children with Asthma

Home-based interventions to improve indoor air quality have demonstrated benefits for asthma morbidity, yet little is known about the effect of environmental interventions in the school setting. We piloted the feasibility and effectiveness of a classroom-based air cleaner intervention to reduce particulate pollutants in classrooms of children with asthma. In this pilot randomized controlled trial, we assessed the effect of air cleaners on indoor air particulate pollutant concentrations in 18 classrooms (9 control, 9 intervention) in 3 urban elementary schools. We enrolled 25 children with asthma (13 control, 12 intervention) aged 6 to 10 years. Classroom air pollutant measurements and spirometry were completed once before and twice after randomization. Asthma symptoms were surveyed every 3 months. Baseline classroom levels of fine particulate matter (particulate matter with diameter of <2.5 μm [PM2.5]) and black carbon (BC) were 6.3 and 0.41 μg/m3, respectively. When comparing the intervention to the control group, classroom PM2.5 levels were reduced by 49% and 42% and BC levels were reduced by 58% and 55% in the first and second follow-up periods, respectively (P < .05 for all comparisons). When comparing the children randomized to intervention and control classrooms, there was a modest improvement in peak flow, but no significant changes in forced expiratory volume in 1 second (FEV1) and asthma symptoms. In this pilot study, a classroom-based air cleaner intervention led to significant reductions in PM2.5 and BC. Future large-scale studies should comprehensively evaluate the effect of school-based environmental interventions on pediatric asthma morbidity.

Investigation of particulate matter performances in relation to chalk selection in classroom environment

This study aims to understand dust generation in classroom indoor for different chalk varieties and their potential doses to receptors in correlation with their physicochemical properties. Two representative chalks of extruded calcium carbonate and moulded gypsum type (total four) were used for writing on ceramic and wooden boards. Chalks were characterized using analytical techniques. Investigation of Particulate Matter (PM): PM2.5, PM10 and Total Suspended Particulate (TSP) concentrations in classroom air generated during the writing and wiping with chalk and board system was done. Dust collected beneath the board was analyzed for particle size distribution. Calcium carbonate made dustless chalks generate less PM during writing and wiping. They are quick settling and non-interacting with receptors, and deliver better utilization of material as compared to gypsum chalks. Physicochemical properties of the chalk constituents were invoked to explain the dust generation and its impact on the user. Surprisingly, dustless chalk made from Gypsum cannot be called really as dustless because of more PM emissions. The age-specific average potential dose for both PM10 and PM2.5 is higher for gypsum chalk as compared to the calcium carbonate chalks. The highest dose was estimated for the children in the age group of 6–11 years.

Complete Genome Sequence of Enterovirus D68 Detected in Classroom Air and on Environmental Surfaces.

We amplified and sequenced the complete genome of enterovirus D68 (EV-D68) that had been collected from classroom air using a filter-based air sampling method and by swab sampling of environmental surfaces. Relatively high levels of EV-D68 genome equivalents were found per cubic meter of air by quantitative real-time reverse transcription-PCR (RT-PCR).

A Passive Opportunity for Improving Air Quality in the Schools Environment: A Real-World Scale Testing

Can passive technology effectively enhance the indoor air quality? To improve classroom indoor air quality, an increase in ventilation and/or air purifiers are often suggested. In this study, a short-term intervention was implemented and investigated to evaluate the effects of a passive adsorbent surface on the pollutant deposition velocity and to improve the overall classroom air quality. We found that furnishing the classroom wall with adsorbent cloth surfaces results in decreased levels of indoor-generated pollutants. The main indoor parameters monitored (CO2, relative humidity, particulate matter) in the presence of a passive sorbent material are lowered: the indoor relative humidity lower than a 7% and carbon dioxide of about 5%. The NO2 deposition velocity has been estimated to 5.1*10-2 (1.8- 6.0)*10-2 cm/s while for SO2 equals to 0.24 (0.02-1.25)*10-2 cm/s. These results suggest that in low-polluted areas, activated carbon cloth may well be used to improve classroom indoor air quality.

Attempt to Improve Indoor Air Quality in Kindergartens

This paper presents the results of the investigation devoted to the quality of indoor air in classrooms of selected Polish kindergartens. The kindergartens buildings were built between 1970 and 1993 and had gravity ventilation systems. The variability of basic IAQ parameters. The outcomes confirmed low quality of the indoor air in these buildings. Certain modifications aimed at improving IAQ were proposed during the investigations. Two solutions were implemented: twofold increase in the volume of supply air and installing indoor air cleaning devices based on the radiant catalytic ionization technology (RCI).

Impact of CO2 concentration on indoor air quality and correlation with relative humidity and indoor air temperature in school buildings in Serbia

Previous studies have shown that poorly ventilated classrooms can have negative impact on the health of children and school staff. In most cases, schools in Serbia are ventilated naturally. Considering their high occupancy, classroom air quality test determines the level of air pollution, after which it is possible to implement corrective measures. The research presented in this study was conducted in four schools which are located in different areas and have different architecture designs. Measurements in these schools have been performed during the winter (heating season) and spring (non-heating season) and the following results were presented: indoor air temperature, relative humidity and carbon dioxide concentration. These results show that the classroom average concentration of carbon dioxide often exceeds the value of 1500 ppm, during its full occupancy, which indicates inadequate ventilation. Measurement campaigns show that carbon dioxide concentration increased significantly from non-heating to heating season in three of the four schools. Analysis of measurements also determined high correlation between relative humidity and carbon dioxide concentration in all schools in winter season. This fact may constitute a solid basis for the fresh air supply strategy.

Dynamics of carbon dioxide concentrations in the air and its effect on the cognitive ability of school students

The carbon dioxide (CO2) production intensity by a secondary school student is studied using a nondispersive infrared CO2 logger for different conditions: relaxation, mental stress, and physical stress. CO2 production measured for mental stress is 24% higher than that for relaxation, while CO2 production for physical stress is more than 2.5 times higher than relaxation levels. Dynamics of CO2 concentration in the classroom air is measured for a typical school building. It is shown that even when the classroom is ventilated between classes, CO2 concentration exceeds 2100 parts per million (ppm), which is significantly higher than the recommended limits defined in developed countries. The ability of seventh-grade school students to perform tasks requiring mental concentration is tested under different CO2 concentration conditions (below 1000 ppm and above 2000 ppm). Five-letter word anagrams are used as test tasks. Statistical analysis of the test results revealed a significant reduction in the number of provided correct answers and an increase in the number of errors when CO2 levels exceeded 2000 ppm.

School Endotoxin Exposure and Asthma Morbidity in Inner-city Children

Endotoxin exposure is associated with airway inflammation. Children spend 6 to 8 h/d in school, yet the effect of school-specific endotoxin exposure on asthma morbidity is not well understood. In this longitudinal cohort study, 248 students with asthma, from 38 inner-city schools, underwent baseline phenotyping and follow-up. Clinical outcomes were evaluated throughout the academic school year and linked to classroom-specific dust and air endotoxin levels as well as home dust endotoxin levels. The primary outcome was maximum asthma symptom-days per 2-week period. Classrooms had higher settled dust endotoxin levels compared with homes (14.3 endotoxin unit/mg vs 11.3 endotoxin unit/mg; P = .02). Airborne endotoxin levels exceeding recommended occupational exposure limits for adults were recorded in 22.0% of classrooms. Classroom air endotoxin levels were independently associated with increased maximum symptom-days in children with nonatopic asthma, but not in those with atopic asthma (interaction P = .03). Adjusting for home exposures, classroom endotoxin exposure was independently associated with a dose-dependent increase in asthma symptom-days for children with nonatopic asthma (adjusted incidence rate ratio, 1.16 [95% CI, 1.03-1.31]; P = .02). In these subjects, maximum symptom-days increased by 1.3 days for each 14-day period when comparing students in classrooms with the lowest endotoxin levels compared with average measured levels. Inner-city children with asthma are exposed to high levels of airborne endotoxin at school, resulting in increased asthma symptoms in children with nonatopic asthma. Mitigation of school-related exposures may represent a strategy to decrease asthma morbidity in this population. ClinicalTrials.gov; No.: NCT01756391; URL: www.clinicaltrials.gov.

Literature Review of the Effect of the Carbon Dioxide Concentration in Classroom Air on the Students' Learning Performance

Literature Review of the Effect of the Carbon Dioxide Concentration in Classroom Air on the Students' Learning Performance

The effect of increased classroom ventilation rate indicated by reduced CO2 concentration on the performance of schoolwork by children.

The article reports on an experiment which investigated the effect of increased classroom ventilation rate on the performance of children aged 10-12years. The experiment was executed at two different schools (two classrooms at each school) as a double-blind 2×2 crossover intervention where four different performance tests were used as surrogates for short-term concentration and logical thinking. Only complete pairs of test responses were included in the within-subject comparisons of performance, and data were not corrected for learning and fatigue effects. Analysis of the total sample suggested the number of correct answers was improved significantly in four of four performance test, addition (6.3%), number comparison (4.8%), grammatical reasoning (3.2%), and reading and comprehension (7.4%), when the outdoor air supply rate was increased from an average of 1.7 (1.4-2.0) to 6.6l/s per person. The increased outdoor air supply rate did not have any significant effect on the number of errors in any of the performance tests. Results from questionnaires regarding pupil perception of the indoor environment, reported Sick Building Syndrome symptoms, and motivation suggested that the study classroom air was perceived more still and pupil were experiencing less pain in the eyes in the recirculation condition compared to the fresh air condition.

Effects of Chalk Use on Dust Exposure and Classroom Air Quality

This study explores human exposure to harmful dust when antidust chalk is used for teaching, as well as dust particle size distribution and how chalk dust affects indoor air quality. In this study, a classroom with 5 ventilation modes was selected. A dust size analyzer and a scanning mobility particle sizer were employed to measure the mass concentration and particle size distribution of chalk dust based on the frequency of chalk use during classes. The results indicate that antidust chalk can generate considerable quantities of dust particles and substantially increase the mass concentration of dust in the proximity of the chalkboard. Approximately 15% of observed chalk dust particles were respirable and high concentrations of chalk dust deteriorated the indoor air quality. Moreover, chalk dust was the primary source of indoor coarse particles. Mechanical ventilation resuspended the settled chalk dust particles, thereby increasing the mass concentration of airborne dust. Using antidust chalk generates coarse, fine, and ultrafine particles, particularly when cleaning the chalkboard. The best ventilation mode to reduce dust accumulated in the chalk teaching classroom was to open doors and turn on ceiling fans. Wearing face masks and increasing distance between seats and blackboard can also prevent teachers and students from chalk dust hazard. The results of this study should serve as a reference for improving indoor air quality and protecting teachers and students from harmful dust particles in classrooms.

Use of visual CO2 feedback as a retrofit solution for improving classroom air quality.

Carbon dioxide (CO2 ) sensors that provide a visual indication were installed in classrooms during normal school operation. During 2-week periods, teachers and students were instructed to open the windows in response to the visual CO2 feedback in 1week and open them, as they would normally do, without visual feedback, in the other week. In the heating season, two pairs of classrooms were monitored, one pair naturally and the other pair mechanically ventilated. In the cooling season, two pairs of naturally ventilated classrooms were monitored, one pair with split cooling in operation and the other pair with no cooling. Classrooms were matched by grade. Providing visual CO2 feedback reduced CO2 levels, as more windows were opened in this condition. This increased energy use for heating and reduced the cooling requirement in summertime. Split cooling reduced the frequency of window opening only when no visual CO2 feedback was present.

Variations in school playground and classroom atmospheric particulate chemistry

The chemical analysis of 553 school playground and classroom PM2.5 filters collected during the BREATHE sampling campaign in Barcelona, Spain, reveals a remarkable degree of spatial and temporal variability in ambient PM composition. Classroom air quality shows average PM2.5 concentrations of 37 μg m−3 (28% higher than outdoors), with much of this mass comprising carbon (including abundant cotton fibres), blackboard chalk particles and silicates. Where sandy playgrounds are present these exert a major influence on inhalable PM2.5 concentrations both indoors and outdoors. Throughout the city there is widespread contamination by metalliferous traffic particles, especially at schools located close to major urban highways where outdoor EC levels can be an order of magnitude higher than in peripheral, green belt schools. Penetration into the classroom of outdoor EC, ammonium sulphate and anthropogenic metals such as Cu, Sn, Sb, Zn and V is pervasive, especially during warmer months. In contrast, levels of nitrate and ammonium are much higher outdoors than in the classroom, especially during winter. During their work and play, schoolchildren across the city respire in a diversity of chemically differing atmospheric microenvironments.

Cooling energy efficiency and classroom air environment of a school building operated by the heat recovery air conditioning unit

The recently-built school buildings have adopted novel heat recovery ventilator and air conditioning system. Heat recovery efficiency of the heat recovery facility and energy conservation ratio of the air conditioning unit were analytically modeled, taking the ventilation networks into account. Following that, school classroom displacement ventilation and its thermal stratification and indoor air quality indicated by the CO2 concentration have been numerically modeled concerning the effects of delivering ventilation flow rate and supplying air temperature. Numerical results indicate that the promotion of mechanical ventilation rate can simultaneously boost the dilution of indoor air pollutants and the non-uniformity of indoor thermal and pollutant distributions. Subsequent energy performance analysis demonstrates that classroom energy demands for ventilation and cooling could be reduced with the promotion of heat recovery efficiency of the ventilation facility, and the energy conservation ratio of the air conditioning unit decreases with the increasing temperatures of supplying air. Fitting correlations of heat recovery ventilation and cooling energy conservation have been presented.

School building energy performance and classroom air environment implemented with the heat recovery heat pump and displacement ventilation system

Recent built low energy school buildings have adopted a novel heat recovery heat pump and classroom ventilation system. School building energy conservation performance and classroom air quality enhancement will be simultaneously investigated in the present work. Heat recovery efficiency of the heat recovery facility and energy conservation ratio of the heat pump unit were analytically modeled, taking the classroom ventilation network into account. Following that, classroom displacement ventilation and its thermal stratification have been investigated concerning the effects of delivering ventilation flow rate and supplying air temperature. Representative thermal comfort parameters, percentage dissatisfied, temperature difference between ankle and head, and draft dissatisfaction have been evaluated. Indoor air quality indicated by the CO2 concentration was also investigated in terms of different levels of ventilation flow rate. Classroom energy demands for ventilation and winter heating have been shown to decrease with the promotion of heat recovery efficiency of the ventilation facility, and the energy conservation ratio of the heat pump increases with temperature of supplying fresh air. Detailed correlations of heat recovery ventilation and heat pump energy conservation have been presented. This research illuminated that enhancement of classroom air quality and reduction of school building energy consumption could be simultaneously achieved with the appropriate operation of heat recovery heat pump and ventilation system.

Exposures to molds in school classrooms of children with asthma

Students spend a large portion of their day in classrooms which may be a source of mold exposure. We examined the diversity and concentrations of molds in inner-city schools and described differences between classrooms within the same school. Classroom airborne mold spores, collected over a 2day period, were measured twice during the school year by direct microscopy. There were 180 classroom air samples collected from 12 schools. Mold was present in 100% of classrooms. Classrooms within the same school had differing mold levels and mold diversity scores. The total mold per classroom was 176.6±4.2 spores/m3 (geometric mean±standard deviation) and ranged from 11.2 to 16,288.5 spores/m3. Mold diversity scores for classroom samples ranged from 1 to 19 (7.7±3.5). The classroom accounted for the majority of variance (62%) in the total mold count, and for the majority of variance (56%) in the mold diversity score versus the school. The species with the highest concentrations and found most commonly included Cladosporium (29.3±4.2 spores/m3), Penicillium/Aspergillus (15.0±5.4 spores/m3), smut spores (12.6±4.0 spores/m3), and basidiospores (6.6±7.1 spores/m3). Our study found that the school is a source of mold exposure, but particularly the classroom microenvironment varies in quantity of spores and species among classrooms within the same school. We also verified that visible mold may be a predictor for higher mold spore counts. Further studies are needed to determine the clinical significance of mold exposure relative to asthma morbidity in sensitized and non-sensitized asthmatic children.

Classroom air quality and pupil attendance and attainment in Aberdeen primary schools

Background and Aims. In addition to indoor pollutant exposures at home, children are also exposed to many of the same pollutants at school and these have been linked to health outcomes. Few studies from the USA and Europe have reported association between reduced ventilation and poorer educational attainment. However, relatively a paucity of information is available to quantify the association in primary school in UK. At this backdrop, we test the hypothesis that classroom carbon dioxide concentration, as an indicator of ventilation rates are inversely related to child school attendance and educational attainment in a cross-sectional study. Methods. Ventilation rates were derived from concentrations of CO2 which were measured over a 3-5 day period in classrooms of children aged 6-7 and 10-11 years. Ventilation rates were related to the class average annual attendance and proportions attaining a national standard for reading, writing and numeracy. Results. Ventilation rates were calculated for 60 naturally ventilated classrooms. The median (interquartile range, IQR) ventilation rate was 7.1l/s/person (5.4, 9.6) and median (IQR) CO2 concentration averaged over the school day was 1122ppm (592-2115). There were positive correlations between classroom ventilation and attendance (rho 0.491 p&lt;0.001) and reading attainment (rho 0.271, p=0.037) but not writing or numeracy. When socioeconomic factors were considered, attendance rose by an average of 0.18% [95% CI 0.06, 0.30] for each l/s/person increase in classroom ventilation. Conclusion. These results provide support for clear association between elevated level of classroom CO2 concentrations and reduced school attendance and reading score. What is unclear is whether poor ventilation directly affects attendance and cognitive ability or is simply a marker for increases in other indoor air pollutants which may produce these effects. There is a need for an intervention study to examine the benefits of increased classroom ventilation in schools.