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.     

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.     

Students' school-level symptoms mediate the relationship between a school's observed moisture problems and students’ subjective perceptions of indoor air quality

Moisture damage can influence the subjective assessment of indoor air quality (subjective IAQ) in various ways. We studied whether the frequency of symptoms reported across students at school level mediates the relationship between observed mold and dampness in a school building and students’ subjective IAQ. To answer this research question, we tested a multilevel path model. The analyzed data were created by merging two nationwide data sets: (a) survey data from students, including information on subjective IAQ (N = 24,786 students); (b) data from schools, including information on mold and dampness in a school building (N = 222). After the background variables were adjusted, schools’ observed mold and dampness were directly and significantly related to poor subjective IAQ (standardized beta (β)= 0.22, P = .002). In addition, in schools with mold and dampness, students reported significantly more symptoms (β = 0.22, P = .023) than in schools without; the higher the prevalence of symptoms at school level, the worse the students’ subjective IAQ (β = 0.60, P < .001). This indirect path was significant (P = .023). In total, schools’ observed mold and dampness and student-reported symptoms explained 52% of the between-school variance in subjective IAQ.     

室内空气品质研究现状与发展

从室内空气品质的定义、室内空气品质的评价室内空气品质问题的起因、通风与室内空气品质的关系、提高室内空气品质的手段等５个方面介绍了国内外有关研究工作的现状。     

Ten questions concerning green buildings and indoor air quality

This paper investigates the concern that green buildings may promote energy efficiency and other aspects of sustainability,but not necessarily the health and w ell-being of occupants through better indoor air quality( IAQ). We ask ten questions to explore IAQ challenges for green buildings as w ell as opportunities to improve IAQ w ithin green buildings and their programs. Our focus is on IAQ,w hile recognizing that many factors influence human health and the healthfulness of a building. We begin w ith an overview of green buildings,IAQ,and w hether and how green building certifications address IAQ.Next,w e examine evidence on w hether green buildings have better IAQ than comparable conventional buildings. Then,w e identify so-called green practices and green products that can have unintended and unfavorable effects on IAQ. Looking ahead,w e offer both immediate and longer-term actions,and a set of research questions,that can help green buildings to more effectively promote IAQ. This article supports a grow ing recognition of the importance of IAQ in green buildings,and the opportunities for improvements. As the World Green Building Council [95] and others have emphasized,people are the most valuable asset of organizations,and efforts to improve IAQ can improve health,w ell-being,productivity,and profitability.     

Indoor air quality and energy performance of air-conditioned office buildings in Singapore

An integrated indoor air quality (IAQ)-energy audit methodology has been developed in this study in Singapore, which provides a rigorous and systematic method of obtaining the status-quo assessment of an 'IAQ signature' in a building. The methodology entails a multi-disciplinary model in obtaining measured data pertaining to different dimensions within the built environment such as the physical, chemical, biological, ventilation, and occupant response characteristics. This paper describes the audit methodology and presents the findings from five air-conditioned office buildings in Singapore. The research has also led to the development of an indoor pollutant standard index (IPSI), which is discussed in this paper. Other performance indicators such as, the ventilation index and the energy index as well as the building symptom index (BSI) are also presented and discussed in the context of an integrated approach to IAQ and energy. Several correlation attempts were made on the various symptoms, indoor air acceptability, thermal comfort, BSI and IPSI, and while BSI values are found to correlate among them as well as with IAQ and THERMAL COMFORT acceptability, no such correlation was observed between BSI and IPSI. This would suggest that the occupants' perception of symptoms experienced as well as environmental acceptability is quite distinct from IAQ acceptability determined from empirical measurements of indoor pollutants, which reinforces the complex nature of IAQ issues.     

Perceptions in the U.S. building industry of the benefits and costs of improving indoor air quality

How building stakeholders (e.g. owners, tenants, operators, and designers) understand impacts of Indoor Air Quality (IAQ) and associated energy costs is unknown. We surveyed 112 stakeholders across the United States to ascertain their perceptions of their current IAQ and estimates of benefits and costs of, as well as willingness to pay for, IAQ improvements. Respondents' perceived IAQ scores correlated with the use of high‐efficiency filters but not with any other IAQ‐improving technologies. We elicited their estimates of the impacts of a ventilation–filtration upgrade (VFU), that is, doubling the ventilation rate from 20 to 40 cfm/person (9.5 to 19 l/s/person) and upgrading from a minimum efficiency reporting value 6 to 11 filter, and compared responses to estimates derived from IAQ literature and energy modeling. Minorities of respondents thought the VFU would positively impact productivity (45%), absenteeism (23%), or health (39%). Respondents' annual VFU cost estimates (mean = $257, s.d. = $496, median = $75 per person) were much higher than ours (always <$32 per person), and the only yearly cost a plurality of respondents said they would pay for the VFU was $15 per person. Respondents holding green building credentials were not more likely to affirm the IAQ benefits of the VFU and were less likely to be willing to pay for it.     

Prospective longitudinal associations between household smoke exposure in early childhood and antisocial behavior at age 12

Young children exert little control over household tobacco smoke exposure, which is considered a developmental neurotoxicant. Using the Quebec Longitudinal Study birth cohort, we examine prospective associations between early childhood smoke exposure and later antisocial behavior. Parents of 1035 children reported on the presence of household smokers at seven follow‐ups from ages 1.5 to 7.5. At age 12, children self‐reported on five aspects of early antisocial dispositions. After adjusting for confounders, every standard deviation increase in household smoke exposure was prospectively associated with a 19% standard deviation unit increase in conduct problems (β=0.07; 95% confidence interval [CI] from 0.04 to 0.09), a 11% standard deviation unit increase in proactive aggression (β=0.04; 95% CI from 0.01 to 0.07), a 13% standard deviation unit increase in reactive aggression (β=0.07; 95% CI from 0.03 to 0.12), a 14% standard deviation unit increase in school indiscipline (β=0.13; 95% CI from 0.05 to 0.20), and a 10% standard deviation unit increase in dropout risk (β=0.07; 95% CI from 0.01 to 0.12). These long‐term findings warrant fostering parental awareness of developmental risks by policy‐makers/health practitioners. School curricula can equally integrate these ideas into their curriculum.     

The associations of indoor environment and psychosocial factors on the subjective evaluation of Indoor Air Quality among lower secondary school students: a multilevel analysis

Subjective evaluation of Indoor Air Quality (subjective IAQ) reflects both building‐related and psychosocial factors, but their associations have rarely been studied other than on the individual level in occupational settings and their interactions have not been assessed. Therefore, we studied whether schools’ observed indoor air problems and psychosocial factors are associated with subjective IAQ and their potential interactions. The analysis was performed with a nationwide sample (N = 195 schools/26946 students) using multilevel modeling. Two datasets were merged: (i) survey data from students, including information on schools’ psychosocial environment and subjective IAQ, and (ii) data from school principals, including information on observed indoor air problems. On the student level, school‐related stress, poor teacher–student relationship, and whether the student did not easily receive help from school personnel, were significantly associated with poor subjective IAQ. On the school level, observed indoor air problem (standardized β = ?0.43) and poor teacher–student relationship (standardized β = ?0.22) were significant predictors of poor subjective IAQ. In addition, school‐related stress was associated with poor subjective IAQ, but only in schools without observed indoor air problem (standardized β = ?0.44).     

School attendance and daily respiratory symptoms in children: influence of moisture damage

We investigated the effect of weekends and school holidays on the daily frequency and severity of respiratory and other symptoms among children attending schools with (index) or without (reference) moisture damage in Spain, the Netherlands, and Finland. Throughout 1 year, parents of 419 children with a respiratory condition attending index (n=15) or reference (n=10) primary schools completed three symptom diaries. We assessed associations between lower respiratory tract, upper respiratory tract or allergy, and other symptom scores and school day, weekend, or summer holiday using mixed regression models stratified by country and moisture damage. We evaluated interactions between moisture damage and type of day. We combined country‐specific estimates (incidence rate ratios [IRRs] and 95% confidence interval [CI]) in meta‐analyses. Symptom scores were lower during weekends and holiday. Lower respiratory tract symptoms were statistically significantly less common during holiday with strongest effect in index schools (IRR=0.7; CI=0.6–0.8). Reporting of other symptoms was more reduced during holiday in index (IRR=0.6; CI=0.4–0.9) than in reference (IRR=0.95; CI=0.8–1.2) schools (interaction P<.01). In conclusion, symptoms were less frequent and/or severe during summer holiday and weekends. This pattern was stronger among children attending moisture‐damaged schools, suggesting potential improvement in moisture damage‐related symptoms during school breaks.     

Machine learning and statistical models for predicting indoor air quality

Indoor air quality (IAQ), as determined by the concentrations of indoor air pollutants, can be predicted using either physically based mechanistic models or statistical models that are driven by measured data. In comparison with mechanistic models mostly used in unoccupied or scenario‐based environments, statistical models have great potential to explore IAQ captured in large measurement campaigns or in real occupied environments. The present study carried out the first literature review of the use of statistical models to predict IAQ. The most commonly used statistical modeling methods were reviewed and their strengths and weaknesses discussed. Thirty‐seven publications, in which statistical models were applied to predict IAQ, were identified. These studies were all published in the past decade, indicating the emergence of the awareness and application of machine learning and statistical modeling in the field of IAQ. The concentrations of indoor particulate matter (PM_2.5 and PM₁₀) were the most frequently studied parameters, followed by carbon dioxide and radon. The most popular statistical models applied to IAQ were artificial neural networks, multiple linear regression, partial least squares, and decision trees.     

Impact of psycho-social factors on perception of the indoor air environment studies in 12 office buildings

The main function of a mechanically ventilated office building is to provide a healthy and comfortable working environment for occupants, while maintaining minimum energy consumption. Twelve mechanically ventilated buildings were selected. They varied greatly in surface area, number of floors, occupant density, and building use. The indoor air quality, thermal comfort, energy consumption, and perception of occupants were investigated in these buildings. A total of 877 subjects participated in the questionnaire survey during the hot summer months of June, July, and August, and during the cold winter months of January, February, and March. The questions included in the questionnaire dealt with health, environmental sensitivity, work area satisfaction, personal control of the workstations environment, and job satisfaction. Measured parameters concerning the quality of indoor air included ventilation rate, concentration of TVOC, CO₂, CO, RH, and formaldehyde. The thermal comfort parameters included room air, mean radiant, plane radiant asymmetry, and dew point temperatures, as well as air velocity and turbulence intensity. Monthly energy consumption data was also gathered for each building. Ventilation performance, in terms of air flow rate and indoor air quality, was compared with the ASHRAE Standard 62-89R (Ventilation for Acceptable Indoor Air Quality. Atlanta: American Society of Heating, Refrigerating, and Air Conditioning Engineers, Inc. U.S.A. [1]). The measured and calculated thermal environmental results were also compared with the ASHRAE Standard 55-92 (Thermal Environmental Conditions for Human Occupancy. Atlanta: American Society of Heating, Refrigerating, and Air Conditioning Engineers, Inc. U.S.A. [2]). CO₂ and CO levels satisfied the recommended limits. The outdoor airflow rate was half that recommended in only one building. The formaldehyde and TVOC levels were moderately higher than suggested comfort levels. However, more than 56% of the occupants rated dissatisfaction with the indoor air quality. Only 63% of the indoor climatic observations fell within the ASHRAE Standard 55-92 summer comfort zone; 27% in the winter. However, only 69% of those surveyed agreed with the comfort zones. More symptoms were reported by workers who perceived IAQ to be poor. Positive relationships were observed between the job satisfaction and satisfaction with office air quality, ventilation, work area temperature, and ratings of work area environment. However, job dissatisfaction did not correlate with symptom reports. The occupants were more dissatisfied with IAQ when they preferred more air movement. In other words, the higher the perceived air movement, the greater the satisfaction with IAQ.     

Indoor air quality in Michigan schools

Indoor air quality (IAQ) parameters in 64 elementary and middle school classrooms in Michigan were examined for the purposes of assessing ventilation rates, levels of volatile organic compounds (VOCs) and bioaerosols, air quality differences within and between schools, and emission sources. In each classroom, bioaerosols, VOCs, CO(2), relative humidity, and temperature were monitored over one workweek, and a comprehensive walkthough survey was completed. Ventilation rates were derived from CO(2) and occupancy data. Ventilation was poor in many of the tested classrooms, e.g., CO(2) concentrations often exceeded 1000 ppm and sometimes 3000 ppm. Most VOCs had low concentrations (mean of individual species <4.5 microg/m(3)); bioaerosol concentrations were moderate (<6500 count per m(3) indoors, <41,000 count per m(3) outdoors). The variability of CO(2), VOC, and bioaerosol concentrations within schools exceeded the variability between schools. These findings suggest that none of the sampled rooms were contaminated and that no building-wide contamination sources were present. However, localized IAQ problems might remain in spaces where contaminant sources are concentrated and that are poorly ventilated. PRACTICAL IMPLICATIONS: Indoor air quality (IAQ) is a continuing concern for students, parents, teachers, and school staff, leading to many complaints regarding poor IAQ. Investigations of these complaints often include air sampling, which must be carefully conducted if representative data are to be collected. To better understand sampling results, investigators need to account for the variability of contaminants both within and between schools.     

Parent’s self-reported indoor environment-related symptoms and health worry increase symptom reports among their children at school—Study in two independent populations

Little is known whether parent's indoor environment quality (IEQ)-related symptoms or health perceptions influence the risk of self- or parent-reported symptoms in their children. We assessed (i) the association of parents’ IEQ-related symptoms with IEQ-related symptoms in their children at school and (ii) whether parental IEQ-related health worry increases the risk for children's symptoms. We used two Finnish studies: a national, population-based survey of indoor air and related health problems (n = 611 parents) and a subset of survey for all primary school pupils (grade 3–6) and their parents in Helsinki, which also included school IEQ-related symptoms reported by children (n = 1617 parent-child dyads). In the school survey, parent's own symptoms increased strongly their reporting of their children's symptoms at school (aOR 4.0, 95% CI 2.7–6.0 for parents experiencing a lot of symptoms) and also symptoms reported by the child itself (aOR 2.2, 95% CI 1.5–3.1). Similar, but slightly weaker associations were seen with parental IEQ-related health worries. Results remained unchanged when adjusted for the IEQ of school buildings or parental and children's allergic diseases. Similar associations were seen in the national survey between parent's symptoms at work and child's symptoms at school. The results suggest that parents’ health perceptions may increase the reporting of children's IEQ-related symptoms even more than is typically seen for many indoor air contaminants.     

Evaluation on sampling point densities for assessing indoor air quality

In Hong Kong, the Environmental Protection Department (HKEPD) has launched an indoor air quality (IAQ) certification scheme to promote an acceptable IAQ in workplaces. However, the associated uncertainties and measurement efforts have not been detailed for practical measurement in indoor spaces. In this study, indoor carbon dioxide (CO₂) concentration is selected as an indicator of the IAQ to investigate the probable errors and measurement efforts in different sampling schemes regarding the sampling point density. In particular, a one-year measurement for sample-spatial average indoor CO₂ concentration at 17 sampling locations in a typical large office (floor area=1200 m²) has been used to evaluate the probable errors of the sample-spatial average concentrations using different sampling point densities. The result shows that the measured concentration at a single sampling point could not be representative for the space and more than one sampling locations would be required in order to increase the measurement accuracy. Mathematical expressions for the sample-spatial average concentration at a confidence level at certain sampling point densities are proposed. When doubled the required measurement points, it was found that the probability of obtaining a measured CO₂ concentration at the confidence level of 95% could be increased from 70% to 90%, as compared with the current sampling practice. It is recommended to specify the measurement uncertainties in future codes so that effort for IAQ measurements in indoor spaces could be determined for practical strategies.     

我国目前室内空气品质改善的对策与措施

强调改善室内空气品质应该有一种紧迫感，不应纠缠一些复杂的理论问题；当务之急是尽快建立起我国的室内空气品质标准和评价方法；尽管将成熟有效的措施和方法应用于实际。从这三方面介绍了应采取的对策和措施。     

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.     

马鞍山市大型商场室内空气质量研究

测试了马鞍山市某商场的甲醛浓度、二氧化碳浓度、微生物菌落数和温度、相对湿度、风速等环境参数,通过问卷调查了营业员和顾客对室内空气质量的评价，客观评价与主观评价的结果表明,商场内空气中主要污染物的浓度符合国家标准,但仍然存在空气质量方面的问题。     

Evaluation of the indoor air quality minimum ventilation rate procedure for use in California retail buildings

This research assesses benefits of adding to California Title‐24 ventilation rate (VR) standards a performance‐based option, similar to the American Society of Heating, Refrigerating, and Air Conditioning Engineers ‘Indoor Air Quality Procedure’ (IAQP) for retail spaces. Ventilation rates and concentrations of contaminants of concern (CoC) were measured in 13 stores. Mass balance models were used to estimate ‘IAQP‐based’ VRs that would maintain concentrations of all CoCs below health‐ or odor‐based reference concentration limits. An intervention study in a ‘big box’ store assessed how the current VR, the Title 24‐prescribed VR, and the IAQP‐based VR (0.24, 0.69, and 1.51 air changes per hour) influenced measured IAQ and perceived of IAQ. Neither current VRs nor Title 24‐prescribed VRs would maintain all CoCs below reference limits in 12 of 13 stores. In the big box store, the IAQP‐based VR kept all CoCs below limits. More than 80% of subjects reported acceptable air quality at all three VRs. In 11 of 13 buildings, saving energy through lower VRs while maintaining acceptable IAQ would require source reduction or gas‐phase air cleaning for CoCs. In only one of the 13 retail stores surveyed, application of the IAQP would have allowed reduced VRs without additional contaminant‐reduction strategies.     

Assessment of ventilation and indoor air pollutants in nursery and elementary schools in France

The aim of this study was to characterize the relationship between Indoor Air Quality (IAQ) and ventilation in French classrooms. Various parameters were measured over one school week, including volatile organic compounds, aldehydes, particulate matter (PM_2.5 mass concentration and number concentration), carbon dioxide (CO₂), air temperature, and relative humidity in 51 classrooms at 17 schools. The ventilation was characterized by several indicators, such as the air exchange rate, ventilation rate (VR), and air stuffiness index (ICONE), that are linked to indoor CO₂ concentration. The influences of the season (heating or non‐heating), type of school (nursery or elementary), and ventilation on the IAQ were studied. Based on the minimum value of 4.2 l/s per person required by the French legislation for mechanically ventilated classrooms, 91% of the classrooms had insufficient ventilation. The VR was significantly higher in mechanically ventilated classrooms compared with naturally ventilated rooms. The correlations between IAQ and ventilation vary according to the location of the primary source of each pollutant (outdoor vs. indoor), and for an indoor source, whether it is associated with occupant activity or continuous emission.