Indoor air microbes and respiratory symptoms of children in moisture damaged and reference schools

Microbial indoor air quality and respiratory symptoms of children were studied in 24 schools with visible moisture and mold problems, and in eight non-damaged schools. School buildings of concrete/brick and wooden construction were included. The indoor environment investigations included technical building inspections for visible moisture signs and microbial sampling using six-stage impactor for viable airborne microbes. Children's health information was collected by questionnaires. The effect of moisture damage on concentrations of fungi was clearly seen in buildings of concrete/brick construction, but not in wooden school buildings. Occurrence of Cladosporium, Aspergillus versicolor, Stachybotrys, and actinobacteria showed some indicator value for moisture damage. Presence of moisture damage in school buildings was a significant risk factor for respiratory symptoms in schoolchildren. Association between moisture damage and respiratory symptoms of children was significant for buildings of concrete/brick construction but not for wooden school buildings. The highest symptom prevalence was found during spring seasons, after a long exposure period in damaged schools. The results emphasize the importance of the building frame as a determinant of exposure and symptoms.     

Parental worry about indoor air quality and student symptom reporting in primary schools with or without indoor air quality problems

Poor indoor air quality (IAQ) in schools is related to increased symptom reporting in students. We investigated whether parental worry about school IAQ influences this association. Data came from survey collected from five Finnish primary schools with observed IAQ problems and five control schools. Parents (n = 1868) of primary school students reported worry about IAQ in schools and symptoms of their children. Associations between observed IAQ problems, worry, and five symptom scores (ie, respiratory, lower respiratory, eye, skin, and general symptoms) were analyzed using multivariate logistic regression and mediation analysis. Parents were on average more worried in schools with observed IAQ problems. Observed IAQ problems were strongly associated with increased worry and all symptoms under study (unadjusted ORs ranged between 1.48 [95% CI 1.48‐2.16] and 2.70 [95% CI 1.52‐5.17]). Parental worry was associated with all symptoms (unadjusted ORs ranged between 2.49 [95% CI 1.75‐3.60] and 4.92 [95% CI 2.77‐9.40]). Mediation analyses suggested that parental worry might partially explain the association between observed IAQ problems and symptom reporting (proportion mediated ranged between 67% and 84% for the different symptoms). However, prospective studies are needed to assess causal relationships between observed IAQ problems, worry, and symptom reporting in schools.     

SCHOOL SEGREGATION,CHARTER SCHOOLS,AND ACCESS TO QUALITY EDUCATION

Race, class, neighborhood, and school quality are all highly interrelated in the U.S. educational system. In the last decade a new factor has come into play, the option of attending a charter school. We offer a comprehensive analysis of the disparities among public schools attended by white, black, Hispanic, Asian, and Native American children in 2010–2011, including all districts in which charter schools existed. We compare schools in terms of poverty concentration, racial composition, and standardized test scores, and we also examine how attending a charter or non‐charter school affects these differences. Black and Hispanic (and to a lesser extent Native American and Asian) students attend elementary and high schools with higher rates of poverty than white students. Especially for whites and Asians, attending a charter school means lower exposure to poverty. Children's own race and the poverty and charter status of their schools affect the test scores and racial isolation of schools that children attend in complex combinations. Most intriguing, attending a charter school means attending a better‐performing school in high‐poverty areas but a lower performing school in low‐poverty areas. Yet even in the best case the positive effect of attending a charter school only slightly offsets the disadvantages of black and Hispanic students.     

Building-related respiratory symptoms can be predicted with semi-quantitative indices of exposure to dampness and mold

Using a semi-quantitative mold exposure index, the National Institute for Occupational Safety and Health (NIOSH) investigated 13 college buildings to examine whether building-related respiratory symptoms among employees are associated with environmental exposure to mold and dampness in buildings. We collected data on upper and lower respiratory symptoms and their building-relatedness, and time spent in specific rooms with a self-administered questionnaires. Trained NIOSH industrial hygienists classified rooms for water stains, visible mold, mold odor, and moisture using semi-quantitative scales and then estimated individual exposure indices weighted by the time spent in specific rooms. The semi-quantitative exposure indices significantly predicted building-related respiratory symptoms, including wheeze [odds ratio (OR) = 2.3; 95% confidence interval (CI) = 1.1-4.5], chest tightness (OR = 2.2; 95% CI = 1.1-4.6), shortness of breath (OR = 2.7; 95% CI = 1.2-6.1), nasal (OR = 2.5; 95% CI = 1.3-4.7) and sinus (OR = 2.2; 95% CI = 1.2-4.1) symptoms, with exposure-response relationships. We found that conditions suggestive of indoor mold exposure at work were associated with building-related respiratory symptoms. Our findings suggest that observational semi-quantitative indices of exposure to dampness and mold can support action to prevent building-related respiratory diseases. PRACTICAL IMPLICATIONS: Current air sampling methods have major limitations in assessing exposure to mold and other biological agents that may prevent the demonstration of associations of bioaerosol exposure with health. Our study demonstrates that semi-quantitative dampness/mold exposure indices, based solely on visual and olfactory observation and weighted by time spent in specific rooms, can predict existence of excessive building-related respiratory symptoms and diseases. Relative extent of water stains, visible mold, mold odor, or moisture can be used to prioritize remediation to reduce potential risk of building-related respiratory diseases. From a public health perspective, these observational findings justify action to correct water leaks and repair water damage in order to prevent building-related respiratory diseases. This approach can also be a basis for developing practical building-diagnostic tools for water-incursion.     

Two Moldy Day-care Centers: a Follow-up Study of Respiratory Symptoms and Infections

Abstract The aim was to study the respiratory symptoms among children exposed to indoor air molds in a day-care environment in Finland. Two day-care centers with a mold problem and two reference day-care centers were included in the study and the health data of the children were collected with a follow-up study of two periods. A total of 229 children 3-7 years old attended the day-care centers. During the first follow-up period, the children in the two day-care centers with mold problems had a significantly increased risk of sore throat, purulent and non-purulent nasal discharge, nasal congestion, hoarseness and common cold. During the second follow-up period, a significantly increased risk of purulent nasal discharge, nasal congestion, hoarseness and cough was observed. Upper respiratory tract symptoms, at least once during the study period, were more prevalent among the children attending mold-problem day-care centers. The mold-exposed children had such symptoms repeatedly or the symptoms were prolonged. In conclusion, in the mold-problem day-care centers, overall morbidity for respiratory symptoms and for common cold increased in comparison with the reference day-care centers.     

Analyzing symptom data in indoor air questionnaires for primary schools

Questionnaires on symptoms and perceived quality of indoor environment are used to assess indoor environment problems, but mainly among adults. The aim of this article was to explore best ways to analyze and report such symptom data, as part of a project to develop a parent‐administered indoor air questionnaire for primary school pupils. Indoor air questionnaire with 25 questions on child's symptoms in the last 4 weeks was sent to parents in five primary schools with indoor air problems and in five control schools. About 83% of parents (N=1470) in case schools and 82% (N=805) in control schools returned the questionnaire. In two schools, 351 (52%) parents answered the questionnaire twice with a 2‐week interval. Based on prevalence of symptoms, their test‐retest repeatability (ICC), and on principal component analysis (PCA), the number of symptoms was reduced to 17 and six symptoms scores were developed. Six variants of these six symptom scores were then formed and their ability to rank schools compared. Four symptom scores (respiratory, lower respiratory, eye, and general symptoms) analyzed dichotomized maintained sufficiently well the diversity of symptom data and captured the between‐school differences in symptom prevalence, when compared to more complex and numerous scores.     

Current wheeze,asthma, respiratory infections,and rhinitis among adults in relation to inspection data and indoor measurements in single‐family houses in Sweden—The BETSI study

In the Swedish Building Energy, Technical Status and Indoor environment study, a total of 1160 adults from 605 single‐family houses answered a questionnaire on respiratory health. Building inspectors investigated the homes and measured temperature, air humidity, air exchange rate, and wood moisture content (in attic and crawl space). Moisture load was calculated as the difference between indoor and outdoor absolute humidity. Totally, 7.3% were smokers, 8.7% had doctor’ diagnosed asthma, 11.2% current wheeze, and 9.5% current asthma symptoms. Totally, 50.3% had respiratory infections and 26.0% rhinitis. The mean air exchange rate was 0.36/h, and the mean moisture load 1.70 g/m³. Damp foundation (OR=1.79, 95% CI 1.16‐2.78) was positively associated while floor constructions with crawl space (OR=0.49, 95% CI 0.29‐0.84) was negatively associated with wheeze. Concrete slabs with overlying insulation (OR=2.21, 95% CI 1.24‐3.92) and brick façade (OR=1.71, 95% CI 1.07‐2.73) were associated with rhinitis. Moisture load was associated with respiratory infections (OR=1.21 per 1 g/m³, 95% CI 1.04‐1.40) and rhinitis (OR=1.36 per 1 g/m³, 95% CI 1.02‐1.83). Air exchange rate was associated with current asthma symptoms (OR=0.85 per 0.1/h, 95% CI 0.73‐0.99). Living in homes with damp foundation, concrete slabs with overlying insulation, brick façade, low ventilation flow, and high moisture load are risk factors for asthma, rhinitis, and respiratory infections.     

Breastfeeding modifies the effects of environment tobacco smoke exposure on respiratory diseases and symptoms in Chinese children: the Seven Northeast Cities Study

To evaluate the potential effect of interaction between breastfeeding and environmental tobacco smoke (ETS) exposure on respiratory health, we studied 31 049 children (aged 2–14 years) from 25 districts of seven cities in northeast China. Parents of the children completed standardized questionnaires that characterized the children's histories of respiratory symptoms and illness, feeding methods, ETS exposure, and other associated risk factors. Breastfeeding was defined as having been mainly breastfed for 3 months or more. The results showed that the association of ETS exposure with childhood respiratory conditions/diseases was modified by breastfeeding, and the association for nonbreastfed children was stronger than that for breastfed children. In particular, for nonbreastfed children, the odds ratios (ORs) for the effect of current ETS exposure asthma was 1.71 (95% CI: 1.43–2.05); however, the OR for breastfed children was 1.33 (95% CI: 1.20–1.48), indicating that the interactions between breastfeeding and current ETS exposure on asthma were statistically significant (P = 0.019). When stratified by school (kindergarten vs. elementary school), breastfeeding was more protective for asthma‐related symptoms among children from kindergarten. In conclusion, this study shows that breastfeeding is associated with smaller associations between ETS exposure and respiratory conditions in children, suggesting that breastfeeding reduces susceptibility to the respiratory effects of ETS.     

Building‐related health symptoms and classroom indoor air quality: a survey of school teachers in New York State

Most previous research on indoor environments and health has studied school children or occupants in non‐school settings. This investigation assessed building‐related health symptoms and classroom characteristics via telephone survey of New York State school teachers. Participants were asked about 14 building‐related symptoms and 23 classroom characteristics potentially related to poor indoor air quality (IAQ). Poisson regression analysis was used to assess the relationship between these symptoms and each classroom characteristic, controlling for potential confounders. About 500 teachers completed the survey. The most frequently reported classroom characteristics included open shelving (70.7%), food eaten in class (65.5%), dust (59.1%), and carpeting (46.9%). The most commonly reported symptoms included sinus problems (16.8%), headache (15.0%), allergies/congestion (14.8%), and throat irritation (14.6%). Experiencing one or more symptoms was associated most strongly with reported dust (relative risk (RR) = 3.67; 95% confidence interval (CI): 2.62–5.13), dust reservoirs (RR = 2.13; 95% CI: 1.72–2.65), paint odors (RR = 1.73; 95% CI: 1.40–2.13), mold (RR = 1.71; 95% CI: 1.39–2.11), and moldy odors (RR = 1.65 95% CI: 1.30–2.10). Stronger associations were found with increasing numbers of reported IAQ‐related classroom characteristics. Similar results were found with having any building‐related allergic/respiratory symptom. This research adds to the body of evidence underscoring the importance to occupant health of school IAQ.     

Microbial growth in building material samples and occupants’ health in severely moisture‐damaged homes

There is no commonly approved approach to detect and quantify the health‐relevant microbial exposure in moisture‐damaged buildings. In 39 single‐family homes with severe moisture damage, we studied whether concentrations of viable microbes in building material samples are associated with health among 71 adults and 68 children, and assessed with symptoms questionnaires, exhaled NO, and peak expiratory flow (PEF) variability. Symptoms were grouped into three scores: upper respiratory symptoms, lower respiratory symptoms, and general symptoms. The homes were divided into three groups based on viable counts of fungi, actinomycetes, and total bacteria cultivated from building material samples. Highest group of actinomycete counts was associated with more general symptoms, worse perceived health, and higher daily PEF variability (aOR 12.51; 1.10‐141.90 as compared to the lowest group) among adults, and with an increase in lower respiratory symptoms in children, but the confidence intervals were wide. We observed significant associations of fungal counts and total microbial score with worse perceived health in adults. No associations with exhaled NO were observed.     

Does dampness and mold in schools affect health? Results of a meta‐analysis

This paper provides meta‐analyses of the published findings relating the respiratory health of occupants of schools with visible dampness, water damage, visible mold, and/or mold odor. Random effects models were used to develop central estimates and confidence limits for the associations of respiratory health effects with school dampness and mold. Eleven studies, all with cross‐sectional designs, were included in the meta‐analyses; however, analyses for some health outcomes were based on as few as four studies. Analyses were performed using data from adults and children combined, using only data from children, and using data from adults and children after excluding two studies. The central estimates of odds ratios from the meta‐analyses were consistently above unity. The evidence of adverse health effects was strongest for cough and wheeze, which had confidence limits excluding unity in some or all analyses. The odds ratios of 1.32 for cough and 1.68 for wheeze suggest moderate increases in health risk. Studies not included in the meta‐analyses provide additional evidence that dampness and mold in schools are associated with adverse health outcomes. These meta‐analyses and the published literature not included in the meta‐analyses suggest that dampness and mold in schools are associated with adverse respiratory health effects.     

Indoor environmental quality in a 'low allergen' school and three standard primary schools in Western Australia

To investigate indoor environmental quality in classrooms, assessments were undertaken in a 'low allergen' school and three standard primary schools in Western Australia. Dust allergens, air pollutants and physical parameters were monitored in the four schools at four times (summer school term, autumn holiday, winter school term and winter holiday) in 2002. The levels of particulate matter (PM(10)) and volatile organic compounds were similar between the four primary schools. Although slightly decreased levels of dust-mite and cat allergens were observed in the 'low allergen' school, the reductions were not statistically significant and the allergen levels in all schools were much lower than the recommended sensitizing thresholds. However, significantly lower levels of relative humidity and formaldehyde level during summer-term were recorded in the 'low allergen' school. In conclusion, the evidence here suggests that the 'low allergen' school did not significantly improve the indoor environmental quality in classrooms. Practical Implications School is an important environment for children in terms of exposure to pollutants and allergens. By assessing the levels of key pollutants and allergens in a low allergen school and three standard primary schools in Western Australia, this study provides useful information for implementation of healthy building design that can improve the indoor environment in schools.     

Microbial exposures in moisture-damaged schools and associations with respiratory symptoms in students: A multi-country environmental exposure study

Moisture-damaged buildings are associated with respiratory symptoms and underlying diseases among building occupants, but the causative agent(s) remain a mystery. We first identified specific fungal and bacterial taxa in classrooms with moisture damage in Finnish and Dutch primary schools. We then investigated associations of the identified moisture damage indicators with respiratory symptoms in more than 2700 students. Finally, we explored whether exposure to specific taxa within the indoor microbiota may explain the association between moisture damage and respiratory health. Schools were assessed for moisture damage through detailed inspections, and the microbial composition of settled dust in electrostatic dustfall collectors was determined using marker-gene analysis. In Finland, there were several positive associations between particular microbial indicators (diversity, richness, individual taxa) and a respiratory symptom score, while in the Netherlands, the associations tended to be mostly inverse and statistically non-significant. In Finland, abundance of the Sphingomonas bacterial genus and endotoxin levels partially explained the associations between moisture damage and symptom score. A few microbial taxa explained part of the associations with health, but overall, the observed associations between damage-associated individual taxa and respiratory health were limited.     

Inflammatory potential in relation to the microbial content of settled dust samples collected from moisture‐damaged and reference schools: results of HITEA study

Aiming to identify factors causing the adverse health effects associated with moisture‐damaged indoor environments, we analyzed immunotoxicological potential of settled dust from moisture‐damaged and reference schools in relation to their microbiological composition. Mouse RAW264.7 macrophages were exposed to settled dust samples (n = 25) collected from moisture‐damaged and reference schools in Spain, the Netherlands, and Finland. After exposure, we analyzed production of inflammatory markers [nitric oxide (NO), tumor necrosis factor‐α (TNF‐)α, interleukin (IL)‐6, and macrophage inflammatory protein (MIP)2] as well as mitochondrial activity, viability, apoptosis, and cell cycle arrest. Furthermore, particle counts, concentration of selected microbial groups as well as chemical markers such as ergosterol, 3‐hydroxy fatty acids, muramic acid, endotoxins, and glucans were measured as markers of exposure. Dust from moisture‐damaged schools in Spain and the Netherlands induced stronger immunotoxicological responses compared to samples from reference schools; the responses to Finnish samples were generally lower with no difference between the schools. In multivariate analysis, IL‐6 and apoptosis responses were most strongly associated with moisture status of the school. The measured responses correlated with several microbial markers and numbers of particles, but the most important predictor of the immunotoxicological potential of settled dust was muramic acid concentration, a marker of Gram‐positive bacteria.     

Extremely-low-frequency magnetic field exposure of children at schools near high voltage transmission lines

Many epidemiological studies have investigated residential exposure to extremely-low-frequency magnetic field (ELF-MF) for children, but exposure at schools where children may stay up to 8 h every weekday was rarely considered. Between March and June 2004, we carried out a field study in Taipei City and County of northern Taiwan to explore ELF-MF exposure pattern among children at schools with high voltage transmission lines (HVTL) running through the campuses. One hundred and one children attending 14 schools with nearby HVTL (exposed group) and 123 children of 18 schools at least 100 m away from HVTL (unexposed group) were monitored for 24-hour personal ELF-MF exposure. Selected classrooms and playgrounds within the buffer regions (i.e., within 30 m of HVTL) and those away from the buffer regions were also assessed, using spot measurements, to determine the extent to which HVTL may contribute to the environmental exposure on campuses. Results show that the two groups didn't differ significantly for both mean exposure and proportion of exposure greater than 0.4 micro-Tesla (microT) estimated for 24 h. However, we noted that 17.8% of the exposed children had a personal mean exposure greater than 0.4 microT during school hours, significantly (p=0.011) higher than that (6.5%) estimated for the unexposed children. An even higher percentage (27.3%) was observed for 11 students with their classrooms intersecting the buffer regions. Playgrounds near buffer regions showed a significantly higher ELF-MF than the other areas of the exposed schools (0.70 vs 0.18 microT, p=0.043). The study demonstrates a wide range of exposures to ELF-MF among school children at campuses adjacent to HVTL. Children attending the exposed schools may have a higher chance of experiencing a mean exposure greater than 0.4 microT during school hours.     

Effects of environmental tobacco smoke on respiratory health of boys and girls from kindergarten: results from 15 districts of northern China

The effects of childhood environmental tobacco smoke (ETS) exposure on respiratory symptoms were investigated in 6053 kindergarten-aged children residing in 15 districts of northern China. Responses to a self-administered questionnaire completed by parents of children from 30 kindergartens were used to ascertain children with persistent cough, persistent phlegm, asthma symptom, current asthma, wheeze and wheeze without asthma. In first 2 years ETS exposure and current ETS exposure were associated with increased prevalence of persistent cough, persistent phlegm, wheeze and wheeze without asthma. Among boys, ETS exposure was associated with more respiratory symptoms and diseases than in girls. ETS exposure during pregnancy was associated with asthma symptom [odds ratio (OR), 3.00; 95% confidence interval (CI): 1.28-7.03], current asthma (OR, 3.38; 95% CI: 1.25-9.14), persistent cough (OR, 1.64; 95% CI: 1.13-2.37), persistent phlegm (OR, 1.74; 95% CI: 1.01-3.01), wheeze (OR, 1.75; 95% CI: 1.15-2.68), and wheeze without asthma (OR, 1.46; 95% CI: 1.01-2.37) only among boys. In boys, the adjusted ORs for increased risk of asthma symptom and current asthma for household exposures (> or =10 cigarettes smoked per day vs. none smoked) during workday were 2.04 (95% CI: 1.01-3.89) and 2.76 (95% CI: 1.06-9.58), respectively. We conclude that ETS exposure increases the occurrence of respiratory symptoms and diseases during childhood. Boys may be more susceptible to ETS than girls. PRACTICAL IMPLICATIONS: Environmental tobacco smoke (ETS) is a highly prevalent respiratory irritant. In agreement with previous cross-sectional studies, our study indicates that exposure to ETS may increase the occurrence of respiratory symptoms and diseases in children, and the association of ETS exposure and respiratory health of children increased in strength with number of cigarettes smoked inside the house per day during workday and day-off. Boys may be more susceptible to ETS than girls. These findings support the view that measures should be taken to reduce ETS exposure for children.     

Pre‐ and postnatal exposure to tobacco smoke and respiratory outcomes during the first year

The different role of prenatal and postnatal exposure to tobacco smoke in respiratory outcomes in infants has not yet been clearly established. Our objective is to assess the effects of these exposures on the risk of respiratory outcomes during the first year of life of infants from a Spanish multicenter cohort study. A total of 2506 women were monitored until delivery. About 2039 infants made up the final population. The outcomes were caused by the occurrence of the following: otitis, cough persisting for more than 3 weeks, lower respiratory tract symptoms (wheezing or chestiness), and lower respiratory tract infections (bronchitis, bronchiolitis, or pneumonia). The relationship between prenatal and postnatal exposure and health outcomes was explored using logistic regression analysis. Maternal smoking during pregnancy increased the odds for wheezing (OR: 1.41, 95% CI: 0.99–2.01) and chestiness (OR: 1.46, 95% CI: 1.03–2.01). Postnatal exposure from fathers was associated with otitis (OR: 1.25, 95% CI: 1.01–1.54). Passive exposure at work of non‐smoking mothers during pregnancy was related to cough (OR: 1.62, 95% CI: 1.05–2.51). Exposure to tobacco smoke was related to a higher risk of experiencing respiratory outcomes in young infants. Prenatal exposure was that most clearly associated with the respiratory outcomes analyzed.     

Oxidative capacity and hemolytic activity of settled dust from moisture‐damaged schools

Exposure to moisture‐damaged indoor environments is associated with adverse respiratory health effects, but responsible factors remain unidentified. In order to explore possible mechanisms behind these effects, the oxidative capacity and hemolytic activity of settled dust samples (n = 25) collected from moisture‐damaged and non‐damaged schools in Spain, the Netherlands, and Finland were evaluated and matched against the microbial content of the sample. Oxidative capacity was determined with plasmid scission assay and hemolytic activity by assessing the damage to isolated human red blood cells. The microbial content of the samples was measured with quantitative PCR assays for selected microbial groups and by analyzing the cell wall markers ergosterol, muramic acid, endotoxins, and glucans. The moisture observations in the schools were associated with some of the microbial components in the dust, and microbial determinants grouped together increased the oxidative capacity. Oxidative capacity was also affected by particle concentration and country of origin. Two out of 14 studied dust samples from moisture‐damaged schools demonstrated some hemolytic activity. The results indicate that the microbial component connected with moisture damage is associated with increased oxidative stress and that hemolysis should be studied further as one possible mechanism contributing to the adverse health effects of moisture‐damaged buildings.     

Allergy and respiratory health effects of dampness and dampness‐related agents in schools and homes: a cross‐sectional study in Danish pupils

Little is known about the health effects of school‐related indoor dampness and microbial exposures. In this study, we investigated dampness and dampness‐related agents in both homes and schools and their association with allergy and respiratory health effects in 330 Danish pupils. Classroom dampness was identified based on technical inspection and bedroom dampness on parents' self‐report. Classroom and bedroom dust was analyzed for seven microbial components. Skin prick testing determined atopic sensitization. Lung function was expressed as z‐scores for forced expiratory volume in one‐second (zFEV₁), forced vital capacity (zFVC) and the ratio zFEV₁/zFVC using GLI‐2012 prediction equations. The parents reported children's allergies, airway symptoms, and doctor‐diagnosed asthma. High classroom dampness, but not bedroom dampness, was negatively associated with zFEV₁ (β‐coef. ?0.71; 95% CI ?1.17 to ?0.23) and zFVC (β‐coef. ?0.52; 95% CI ?0.98 to ?0.06) and positively with wheezing (OR 8.09; 95% CI 1.49 to 43.97). No consistent findings were found between any individual microbial components or combination of microbial components and health outcomes. Among other indoor risk factors, environmental tobacco smoke (ETS) decreased zFEV₁ (β‐coef. ?0.22; 95% CI ?0.42 to ?0.02) and zFEV₁/zFVCratio (β‐coef. ?0.26; 95% CI ?0.44 to ?0.07) and increased upper airway symptoms (OR 1.66; 95% CI 1.03–2.66). In conclusion, dampness in classrooms may have adverse respiratory health effects in pupils, but microbial agents responsible for this effect remain unknown.