The prevalence and incidence of sick building syndrome in Chinese pupils in relation to the school environment: a two-year follow-up study

TFOS Lifestyle Report: Impact of environmental conditions on the ocular surface

Environmental risk factors that have an impact on the ocular surface were reviewed and associations with age and sex, race/ethnicity, geographical area, seasonality, prevalence and possible interactions between risk factors are reviewed. Environmental factors can be (a) climate-related: temperature, humidity, wind speed, altitude, dew point, ultraviolet light, and allergen or (b) outdoor and indoor pollution: gases, particulate matter, and other sources of airborne pollutants. Temperature affects ocular surface homeostasis directly and indirectly, precipitating ocular surface diseases and/or symptoms, including trachoma. Humidity is negatively associated with dry eye disease. There is little data on wind speed and dewpoint. High altitude and ultraviolet light exposure are associated with pterygium, ocular surface degenerations and neoplastic disease. Pollution is associated with dry eye disease and conjunctivitis. Primary Sjögren syndrome is associated with exposure to chemical solvents. Living within a potential zone of active volcanic eruption is associated with eye irritation. Indoor pollution, "sick" building or house can also be associated with eye irritation. Most ocular surface conditions are multifactorial, and several environmental factors may contribute to specific diseases. A systematic review was conducted to answer the following research question: "What are the associations between outdoor environment pollution and signs or symptoms of dry eye disease in humans?" Dry eye disease is associated with air pollution (from NO2) and soil pollution (from chromium), but not from air pollution from CO or PM10. Future research should adequately account for confounders, follow up over time, and report results separately for ocular surface findings, including signs and symptoms.

Determining ventilation strategies to relieve health symptoms among school occupants

Purpose

Poor indoor air quality (IAQ) contributing to occupants’ health symptoms is a universal, typically ventilation-related, problem in schools. In cold climates, low-cost strategies to improve IAQ in a naturally ventilated school are rare since conventional methods, such as window opening, are often inappropriate. This paper aims to present an investigation of strategies to relieve health symptoms among school occupants in naturally ventilated school in Finland.

Design/methodology/approach

A case study approach is adopted to thoroughly investigate the process of generating the alternatives of ventilation redesign in a naturally ventilated school where there have been complaints of health symptoms. First, the potential sources of the occupants’ symptoms are identified. Then, the strategies aiming to reduce the symptoms are compared and evaluated.

Findings

In a naturally ventilated school, health symptoms that are significantly caused by insufficient ventilation can be potentially reduced by implementing a supply and exhaust ventilation system. Alternatively, it is possible to retain the natural ventilation with reduced number of occupants. The selected strategy would depend considerably on the desired number of users, the budget and the possibilities to combine the redesign of ventilation with other refurbishment actions. Furthermore, the risk of poorer indoor air caused by the refurbishment actions must also be addressed and considered.

Practical implications

This study may assist municipal authorities and school directors in decisions concerning improvement of classroom IAQ and elimination of building-related symptoms. This research provides economic aspects of alternative strategies and points out the risks related to major refurbishment actions.

Originality/value

Since this study presents a set of features related to indoor air that contribute to occupants’ health as well as matters to be considered when aiming to decrease occupants’ symptoms, it may be of assistance to municipal authorities and practitioners in providing a healthier indoor environment for pupils and teachers.

Effects of occupant behaviors on perceived dormitory air quality and sick building syndrome symptoms among female college students

We performed a cross-sectional survey of 2143 female students in a university in Tianjin, China regarding perceived air quality (PAQ) and sick building syndrome (SBS) symptoms in the student dormitory. The prevalence of general, mucosal, and skin symptoms was 22.1%, 21.9%, and 26.3%, respectively. The three most prevalent PAQ complaints were "dry air" (48.9% often), "stuffy odor" (18.2%), and "other unpleasant odors" (5.1%), and they were significant risk factors for 11-12 out of 12 SBS symptoms (adjusted odds ratios [AOR]: 1.6-5.8). Survey data of 1471 undergraduates, whose dorms were of uniform layout and furnishing, were used to further investigate the influences of occupancy level and occupant behaviors on PAQ and SBS symptoms. Frequent use of air freshener/perfume was a significant risk factor for "dry air," less frequent room cleaning and higher occupancy density were significant risk factors for "stuffy odor," and less natural ventilation was a significant risk factor for both "stuffy odor" and "pungent odor." These factors were also significantly associated with some SBS symptoms. In particular, the use of air freshener/perfume exhibited a significant dose-response pattern with "fatigue" (sometimes: AOR 1.3; often: AOR 2.0) and with "irritated, stuffy, or runny nose" (sometimes: AOR 1.6; often: AOR 2.2).

Assessment of sick building syndrome using visual analog scales

BACKGROUND

Despite there is no recommendations for assessing symptoms of sick building syndrome, the use of visual analog scales (VAS) seems attractive and appropriate. We aimed to demonstrate the benefits of using VAS for evaluating subjective symptoms of sick building syndrome.

METHOD

We compared an exposed group to a control group with a one-year follow-up. To assess chronology of symptoms, employees were asked to complete four VAS at different times: after vacations (time 1), beginning of the week-beginning of the day (time 2), beginning of the week-end of the day (time 3), and end of the week-end of the day (time 4). Measurements were repeated before and after ventilation work for the exposed group and at the same time in the control group without intervention. Confounding factors were assessed.

RESULTS

We included 36 employees (21 in the exposed group and 15 in the control group). Both groups were comparable. Prior to ventilation work, the exposed group had more subjective symptoms than the control group with a chronology of symptoms. After ventilation work, symptoms did not differ between groups, and most symptoms decreased within the exposed group.

PRACTICAL IMPLICATION

The use of VAS provided reliable data for assessing sick building syndrome and showed a dose-response relationship between occupational exposure and symptoms.

Humidification of indoor air for preventing or reducing dryness symptoms or upper respiratory infections in educational settings and at the workplace

BACKGROUND

Indoor exposure to dry air during heating periods has been associated with dryness and irritation symptoms of the upper respiratory airways and the skin. The irritated or damaged mucous membrane poses an important entry port for pathogens causing respiratory infections.

OBJECTIVES

To determine the effectiveness of interventions that increase indoor air humidity in order to reduce or prevent dryness symptoms of the eyes, the skin and the upper respiratory tract (URT) or URT infections, at work and in educational settings.

SEARCH METHODS

The last search for all databases was done in December 2020. We searched Ovid MEDLINE, Embase, CENTRAL (Cochrane Library), PsycINFO, Web of Science, Scopus and in the field of occupational safety and health: NIOSHTIC-2, HSELINE, CISDOC and the In-house database of the Division of Occupational and Environmental Medicine, University of Zurich. We also contacted experts, screened reference lists of included trials, relevant reviews and consulted the WHO International Clinical Trials Registry Platform (ICTRP).

SELECTION CRITERIA

We included controlled studies with a parallel group or cross-over design, quasi-randomised studies, controlled before-and-after and interrupted time-series studies on the effects of indoor air humidification in reducing or preventing dryness symptoms and upper respiratory tract infections as primary outcomes at workplace and in the educational setting. As secondary outcomes we considered perceived air quality, other adverse events, sick leave, task performance, productivity and attendance and costs of the intervention.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles, abstracts and full texts for eligibility, extracted data and assessed the risks of bias of included studies. We synthesised the evidence for the primary outcomes 'dry eye', 'dry nose', 'dry skin', for the secondary outcome 'absenteeism', as well as for 'perception of stuffiness' as the harm-related measure. We assessed the certainty of evidence using the GRADE system.

MAIN RESULTS

We included 13 studies with at least 4551 participants, and extracted the data of 12 studies with at least 4447 participants. Seven studies targeted the occupational setting, with three studies comprising office workers and four hospital staff. Three of them were clustered cross-over studies with 846 participants (one cRCT), one parallel-group controlled trial (2395 participants) and three controlled before-and-after studies with 181 participants. Five studies, all CTs, with at least 1025 participants, addressing the educational setting, were reported between 1963 and 1975, and in 2018. In total, at least 3933 (88%) participants were included in the data analyses. Due to the lack of information, the results of the risk of bias assessment remained mainly unclear and the assessable risks of bias of included studies were considered as predominantly high. Primary outcomes in occupational setting:  We found that indoor air humidification at the workplace may have little to no effect on dryness symptoms of the eye and nose (URT). The only cRCT showed a significant decrease in dry eye symptoms among working adults (odds ratio (OR) 0.54, 95% confidence interval (CI) 0.37 to 0.79) with a low certainty of the evidence. The only cluster non-randomised cross-over study showed a non-significant positive effect of humidification on dryness nose symptoms (OR 0.87, 95% CI 0.53 to 1.42) with a low certainty of evidence. We found that indoor air humidification at the workplace may have little and non-significant effect on dryness skin symptoms. The pooled results of two cluster non-RCTs showed a non-significant alleviation of skin dryness following indoor air humidification (OR 0.66, 95% CI 0.33 to 1.32) with a low certainty of evidence. Similarly, the pooled results of two before-after studies yielded no statistically significant result (OR 0.69, 95% CI 0.33 to 1.47) with very low certainty of evidence No studies reported on the outcome of upper respiratory tract infections. No studies conducted in educational settings investigated our primary outcomes. Secondary outcomes in occupational setting: Perceived stuffiness of the air was increased during the humidification in the two cross-over studies (OR 2.18, 95% CI 1.47 to 3.23); (OR 1.70, 95% CI 1.10 to 2.61) with low certainty of evidence. Secondary outcomes in educational setting: Based on different measures and settings of absenteeism, four of the six controlled studies found a reduction in absenteeism following indoor air humidification (OR 0.54, 95% CI 0.45 to 0.65; OR 0.38, 95% CI 0.15 to 0.96; proportion 4.63% versus 5.08%).

AUTHORS' CONCLUSIONS

Indoor air humidification at the workplace may have little to no effect on dryness symptoms of the eyes, the skin and the URT. Studies investigating illness-related absenteeism from work or school could only be summarised narratively, due to different outcome measures assessed. The evidence suggests that increasing humidification may reduce the absenteeism, but the evidence is very uncertain. Future RCTs involving larger sample sizes, assessing dryness symptoms more technically or rigorously defining absenteeism and controlling for potential confounders are therefore needed to determine whether increasing indoor air humidity can reduce or prevent dryness symptoms of the eyes, the skin, the URT or URT infections at work and in educational settings over time.

Harmonization and Visualization of Data from a Transnational Multi-Sensor Personal Exposure Campaign

Use of a multi-sensor approach can provide citizens with holistic insights into the air quality of their immediate surroundings and their personal exposure to urban stressors. Our work, as part of the ICARUS H2020 project, which included over 600 participants from seven European cities, discusses the data fusion and harmonization of a diverse set of multi-sensor data streams to provide a comprehensive and understandable report for participants. Harmonizing the data streams identified issues with the sensor devices and protocols, such as non-uniform timestamps, data gaps, difficult data retrieval from commercial devices, and coarse activity data logging. Our process of data fusion and harmonization allowed us to automate visualizations and reports, and consequently provide each participant with a detailed individualized report. Results showed that a key solution was to streamline the code and speed up the process, which necessitated certain compromises in visualizing the data. A thought-out process of data fusion and harmonization of a diverse set of multi-sensor data streams considerably improved the quality and quantity of distilled data that a research participant received. Though automation considerably accelerated the production of the reports, manual and structured double checks are strongly recommended.

Improving the IAQ for Learning Efficiency with Indoor Plants in University Classrooms in Ajman, United Arab Emirates

The objective of this paper is to investigate the effect of improving indoor air quality with indoor plants. As a methodology, two target classrooms with the same size (120.64 m2) and 32 students per room were selected. Then, 48 areca palm pots (average leaf area of 300 cm2/pot) were placed, and the plant density was 14.68% of the floor area. Subjective assessment for general questions, learning motivation, perceived air quality, and SBS symptoms was conducted at 5 min after the class started and 5 min before the class ended. The results showed that the CO2 concentration by respiration of the students (average of 1873 ppm) exceeded the regulatory standard (1000 ppm), but the students did not recognize the indoor CO2 concentration. The increase in CO2 concentration in the classroom was lower in the case with plant placement (624 ppm) compared with the case without plant placement (about 1205 ppm). It was statistically proven that the CO2 concentration by respiration could be reduced by 50% if the indoor plant leaf area density were maintained at about 14.68% of the floor area. In the case with plant placement, the students perceived the indoor air quality to be 40% fresher and showed a 140% higher acceptability. Moreover, the complaining of SBS symptoms was improved by 108%, and the students’ perception that it was better to focus on learning increased by about 120%. As the awareness of sustainability increases, indoor plants will be more actively placed in the United Arab Emirates. Indoor plants not only provide a visual green effect to improve human comfort but also purify indoor air pollutants.

Association of subjective health symptoms with indoor air quality in European office buildings: The OFFICAIR project

The aim of this study was to explore the association between the building-related occupants' reported health symptoms and the indoor pollutant concentrations in a sample of 148 office rooms, within the framework of the European OFFICAIR research project. A large field campaign was performed in 37 office buildings among eight countries, which included (a) 5-day air sampling of volatile organic compounds (VOCs), aldehydes, ozone, and NO₂ (b) collection of information from 1299 participants regarding their personal characteristics and health perception at workplace using online questionnaires. Stepwise and multilevel logistic regressions were applied to investigate associations between health symptoms and pollutant concentrations considering personal characteristics as confounders. Occupants of offices with higher pollutant concentrations were more likely to report health symptoms. Among the studied VOCs, xylenes were associated with general (such as headache and tiredness) and skin symptoms, ethylbenzene with eye irritation and respiratory symptoms, a-pinene with respiratory and heart symptoms, d-limonene with general symptoms, and styrene with skin symptoms. Among aldehydes, formaldehyde was associated with respiratory and general symptoms, acrolein with respiratory symptoms, propionaldehyde with respiratory, general, and heart symptoms, and hexanal with general SBS. Ozone was associated with almost all symptom groups.

Lifestyle behaviors and home and school environment in association with sick building syndrome among elementary school children: a cross-sectional study

Background

Sick building syndrome (SBS) refers to the combination of symptoms experienced by occupants of specific building characteristics. This study investigated the associations of children’s lifestyle behaviors, allergies, home, and school environment with SBS symptoms.

Methods

A total of 4408 elementary school children living in Sapporo City, Japan participated in this study. SBS was determined on parental answers to MM080 standardized school questionnaires on symptoms that were weekly experienced by these children, and if the symptom is attributed to their home or school environment. The Japanese version of the International Study of Asthma and Allergies in Childhood questionnaire was used to assess wheeze, rhino-conjunctivitis, and eczema. A logistic regression analysis was conducted to evaluate the associations between SBS symptoms and variables by controlling the potential confounders (gender, grade, school, and parental history of allergies). A stepwise backward elimination was conducted to assess independent variables related to SBS.

Results

Participants revealed mucosal (6.9%), skin (2.0%), and general (0.8%) symptoms. The presence of one or more allergy was associated with increased mucosal and skin symptoms. Children who skipped breakfast, displayed faddiness (like/dislike of food), had constipation, have insufficient sleep, did not feel refreshed after sleep, and lacked deep sleep showed significantly high odds ratios with SBS symptoms. The stepwise analysis showed faddiness for mucosal symptoms and not feeling refreshed after sleep for mucosal and skin symptoms, whereas constipation and lacking deep sleep for general symptoms were independent variables in increasing the symptoms. We found no significant relationship between SBS in children and schools. Considering children’s home, old building, no ventilation, wall-to-wall carpet, and heavy nearby traffic were associated with elevated mucosal symptom, while living in a multifamily home increased general symptoms. Home dampness was an independent variable in increasing all SBS symptoms.

Conclusions

Allergies and lifestyle behaviors were associated with increased SBS in children, including skipping breakfast, displaying faddiness, constipation, insufficient sleep, not feeling refreshed after sleep, and the lack of deep sleep. Further, dampness at home was associated with increase in all SBS symptoms. Lifestyle (e.g., eating and sleeping habits) and home (i.e., dampness) improvements might alleviate SBS symptoms in children.

Effects of filtered fresh air ventilation on classroom indoor air and biomarkers in saliva and nasal samples: A randomized crossover intervention study in preschool children

To evaluate the short-term effects of filtered fresh air ventilation system on classroom indoor air and biomarkers in saliva and nasal samples in preschool children, a randomized crossover study was conducted in a kindergarten in Shanghai, China in 2016. Two classrooms at the same grade (n = 43) were selected and fresh air ventilation systems (FAVS) with high efficiency particulate air filter (HEPA) were installed. In the first week, FAVS-HEPA was run in one classroom for 2 continuous school days and the other classroom was remained as usual with no use of FAVS-HEPA. After one week of wash-out, the ventilation modes exchanged between two classrooms and another 2 days of intervention were repeated. Real-time indoor and outdoor air pollution and climate factors (PM_2.5, Temp and relative humidity (R.H.)) were measured. Saliva and nasal internal mucosa samples were collected immediately at the end of each intervention scenario. Linear mixed-effect regression model was applied to evaluate the effects of intervention on children's health indicators controlling for age, gender, height, BMI and temperature. The results showed, with FAVS-HEPA, the classroom indoor fine particulate matter (PM_2.5)(29.1 ± 17.9 μg/m³) was on average significantly lower than that without FAVS-HEPA (85.7 ± 43.2 μg/m³). By regression analysis, each 10 μg/m³ decrease of indoor PM_2.5 during the 8 school hours in the first intervention day was associated with an average of 1.76% (95% confidence interval (CI) 0.43-3.08%) increase in saliva lysozyme. This percentage increased to 2.41% (95%CI 0.52-4.26%) if related to the PM_2.5 level in 16 school hours over 2 days of intervention. A total of 19 nasal bacterial taxa were lower in subjects exposed to FAVS-HEPA, compared to that with no use of FAVS-HEPA, despite the general bacteria diversity levels in nasal samples were not statistically different. Among others, Providencia species showed significant effects in mediating the associations between higher PM_2.5 and lower lysozyme. In conclusion, using FAVS-HEPA was effective in decreasing the classroom indoor PM_2.5. Saliva lysozyme, as a non-specific immune biomarker, was significantly inversely associated with indoor PM_2.5. Certain nasal bacteria might play key roles in mediating PM_2.5 exposure and children's lysozyme levels.

Municipal challenges in managing a building with noted health symptoms

Purpose

This study aims to present property management challenges that municipalities have encountered regarding a public building with noted building-related symptoms. The study goes on to provide reasons for the failure of attempts to manage the symptoms and discusses the current challenges concerning the process.

Design/methodology/approach

A participatory case study was used as the research methodology to identify the current challenges concerning a municipal approach to managing the building-related symptoms in a case-study building. The researchers scrutinised the history of the health symptom management process and attended the project planning meetings focused on the investigation of the condition of the building.

Findings

Multiple challenges concerning maintenance and omitted or postponed repair actions, as well as vagueness in the management process were found. In addition to this, it was noted that the complexity of the initial design of the building and vandalism have resulted in challenges for the maintenance and moisture performance of the building structures. According to the study, more orderliness and a more systematic process is needed when managing a municipal property.

Practical implications

The identified property management challenges may be of practical value for the facility managers and the property owners, especially when managing the building-related symptoms and a damaged building.

Originality/value

This study highlights the importance of having an in-depth understanding of condition assessments as well as proper maintenance and timely repairs for the successful management of the building-related symptoms in a municipal building. This is a pilot project in a larger project of management of building refurbishment.

Human exposure to NO2 in school and office indoor environments

BACKGROUND

Although nitrogen dioxide (NO₂) is one of the most common air pollutants encountered indoors, and extensive literature has examined the link between NO₂ exposure and duration causing adverse respiratory effects in susceptible populations, information about global and local exposure to NO₂ in different indoor environments is limited. To synthesize the existing knowledge, this review analyzes the magnitude of and the trends in global and local exposure to NO₂ in schools and offices, and the factors that control exposure.

METHODS

For the literature review, Web of Science, SCOPUS, Google Scholar, and PubMed were searched using 42 search terms and their combinations to identify manuscripts, reports, and directives published between 1971 and 2019. The search was then extended to the reference lists of relevant articles.

RESULTS

The calculated median, as well as the mean, concentration of NO₂ in school (median 21.1 μg/m³; mean 29.4 μg/m³) and office settings (median 22.7 μg/m³; mean 25.1 μg/m³) was well below the World Health Organization (WHO) guideline of 40 μg/m³ for the annual mean NO₂ concentration. However, a large range of average concentrations of NO₂ were reported, from 6.00 to 68.5 μg/m³ and from 3.40 to 56.5 μg/m³ for school and office environments, respectively, indicating situations where the WHO guidelines are exceeded. Outdoor levels of NO₂ are a reliable predictor of indoor NO₂ levels across seasons, with mean and median Indoor/Outdoor (I/O) ratios of 0.9 and 0.7 in school and 0.9 and 0.8 in office environments, respectively. The absence of major indoor NO₂ emission sources and NO₂ sinks, including chemical reactions and deposition, are the reasons for lower indoor NO₂ concentrations. During the winter, outdoor NO₂ concentrations are generally higher than during the summer. In addition, various building and indoor environment characteristics, such as type of ventilation, air exchange rates, airtightness of the envelope, furnishing and surface characteristics of the building, location of the building (urban versus suburban and proximity to traffic routes), as well as occupants' behavior (such as opening windows), have been statistically significantly associated with indoor NO₂ levels in school and office environments.

CONCLUSIONS

Indoor exposure to NO₂ from the infiltration of ambient air can be significant in urban areas, and in the case of high traffic volume. Although reducing transportation emissions is challenging, there are several easier means to reduce indoor NO₂ concentrations, including a ventilation strategy with suitable filters; location planning of new schools, classrooms, and ventilating windows or intakes; traffic planning (location and density); and reducing the use of NO₂-releasing indoor sources.

Onset of respiratory symptoms among Chinese students: associations with dampness and redecoration, PM10, NO2, SO2 and inadequate ventilation in the school

Objective: To study onset of respiratory symptoms among students in China in relation to the school and the home environment. Methods: A two-year prospective cohort study among 1325 students in eight schools. Air pollution was measured at baseline in the schools. Respiratory symptoms and the home environment were assessed by a questionnaire. Results: The 2-year onset was 14.3%, 23.2%, 15.4%, 4.7% and 37.3% for wheeze, daytime attacks of breathlessness, nocturnal cough, nocturnal wheeze/breathlessness and respiratory infections, respectively. The mean concentrations of PM₁₀, SO₂, NO_2, ozone and CO₂ in the classrooms were 129 µg/m³, 68.0 µg/m³, 43.2 µg/m³, 8.6 µg/m³ and 1208 ppm, respectively. Environmental tobacco smoke (ETS), dampness/mold at home and ozone in the classroom were associated with onset of wheeze. Onset of daytime breathlessness was associated with redecoration and dampness/mold at home and CO₂ and relative air humidity (RH) in the classrooms. Dampness/mold at home, PM₁₀, CO₂ and RH in the classrooms and outdoor PM₁₀, SO₂ and NO₂ were associated with onset of nocturnal cough. Onset of nocturnal wheeze/breathlessness was associated with dampness/mold at home and RH and PM₁₀ in the classrooms. Respiratory infections were more common at higher levels of outdoor PM₁₀. Conclusions: Air pollution (PM₁₀, ozone, SO₂ and NO₂) and inadequate ventilation flow in the classrooms (indicated by CO₂ > 1000 ppm) and ETS, dampness or mold and chemical emissions from redecoration at home can increase onset of respiratory symptoms.

Spatiotemporal variations and relationship of PM and gaseous pollutants based on gray correlation analysis

The present work characterizes the spatiotemporal variations of air pollution at four sites in Xi'an city. The investigations lasted for 1 year: January 1 through December 31, 2015. The concentrations of CO, NO₂, O₃, PM and SO₂ were systematically monitored. The gray correlation analysis was used to correlate PM_2.5 and gaseous pollutants. The formation mechanisms of sulfate and nitrate aerosols were discussed. Results clearly revealed severe air pollution by PM_2.5, PM₁₀ and NO₂ at all four sites. Significant monthly variations were observed for PM_2.5, PM₁₀, SO₂ and CO with the maximum values in December/January and minimum values in June/July. The O₃ level showed an opposite trend. Spatially, high variations were observed for PM and some gaseous pollutants at individual sites. Gray correlation analysis revealed the significance of various major influencing factors on seasonal PM_2.5 values at each site. In general, PM₁₀, SO₂ and NO₂ affect the PM_2.5 more than other pollutants. For a more efficient control of air pollution, a systematic spatial characterization of the seasonal variability of individual influencing factors is necessary.

Synthesis of zeolitic imidazolate framework-8 on polyester fiber for PM2.5 removal

Zeolitic imidazolate framework-8 (ZIF-8) was introduced on the surface of fibers of a non-woven fabric made of polyethylene terephthalate (PET). The phase structure, morphology, textural properties and chemical structure were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen (N₂) adsorption analyzer and Fourier transform infrared spectroscopy (FTIR). The XRD, SEM and FTIR results indicated that ZIF-8 had been successfully coated on the PET fibers. N₂ adsorption analyses suggested that addition of ZIF-8 significantly increased the specific surface and micropore volume of composites. The PM_2.5 removal experiment showed the filtration efficiency of ZIF-8/PET was twice as high as that of pure PET. Meanwhile, ZIF-8/PET also displayed a low pressure drop and good recycling performance. This research provided a facile method to deposit active ZIF-8 onto polymers with low air resistance, and that ZIF-8/PET was a good candidate as an air filter for PM_2.5 removal.

Zeolitic imidazolate framework-8 (ZIF-8) was introduced on the surface of fibers of a non-woven fabric made of polyethylene terephthalate (PET).

Investigation on Indoor Air Pollution and Childhood Allergies in Households in Six Chinese Cities by Subjective Survey and Field Measurements

Greater attention is currently being paid to the relationship between indoor environment and childhood allergies, however, the lack of reliable data and the disparity among different areas hinders reliable assessment of the relationship. This study focuses on the effect of indoor pollution on Chinese schoolchildren and the relationship between specific household and health problems suffered. The epidemiological questionnaire survey and the field measurement of the indoor thermal environment and primary air pollutants including CO₂, fine particulate matter (PM_2.5), chemical pollutants and fungi were performed in six Chinese cities. A total of 912 questionnaires were eligible for statistical analyses and sixty houses with schoolchildren aged 9-12 were selected for field investigation. Compared with Chinese national standards, inappropriate indoor relative humidity (<30% or >70%), CO₂ concentration exceeding 1000 ppm and high PM_2.5 levels were found in some monitored houses. Di(2-ethylhexyl) phthalate (DEHP) and dibutyl phthalate (DBP) were the most frequently detected semi-volatile organic compounds (SVOCs) in house dust. Cladosporium, Aspergillus and Penicillium were detected in both indoor air and house dust. This study indicates that a thermal environment with CO₂ exceeding 1000 ppm, DEHP and DBP exceeding 1000 μg/g, and high level of PM_2.5, Cladosporium, Aspergillus and Penicillium increases the risk of children's allergies.

Volatile organic compounds (VOC), formaldehyde and nitrogen dioxide (NO2) in schools in Johor Bahru, Malaysia: Associations with rhinitis, ocular, throat and dermal symptoms, headache and fatigue

This paper studied associations between volatile organic compounds (VOC), formaldehyde, nitrogen dioxide (NO₂) and carbon dioxide (CO₂) in schools in Malaysia and rhinitis, ocular, nasal and dermal symptoms, headache and fatigue among students. Pupils from eight randomly selected junior high schools in Johor Bahru, Malaysia (N=462), participated (96%). VOC, formaldehyde and NO₂ were measured by diffusion sampling (one week) and VOC also by pumped air sampling during class. Associations were calculated by multi-level logistic regression adjusting for personal factors, the home environment and microbial compounds in the school dust. The prevalence of weekly rhinitis, ocular, throat and dermal symptoms were 18.8%, 11.6%, 15.6%, and 11.1%, respectively. Totally 20.6% had weekly headache and 22.1% fatigue. Indoor CO₂ were low (range 380-690 ppm). Indoor median NO₂ and formaldehyde concentrations over one week were 23μg/m³ and 2.0μg/m³, respectively. Median indoor concentration of toluene, ethylbenzene, xylene, and limonene over one week were 12.3, 1.6, 78.4 and 3.4μg/m³, respectively. For benzaldehyde, the mean indoor concentration was 2.0μg/m³ (median<1μg/m³). Median indoor levels during class of benzene and cyclohexane were 4.6 and 3.7μg/m³, respectively. NO₂ was associated with ocular symptoms (p<0.001) and fatigue (p=0.01). Formaldehyde was associated with ocular (p=0.004), throat symptoms (p=0.006) and fatigue (p=0.001). Xylene was associated with fatigue (p<0.001) and benzaldehyde was associated with headache (p=0.03). In conclusion, xylene, benzaldehyde, formaldehyde and NO₂ in schools can be risk factors for ocular and throat symptoms and fatigue among students in Malaysia. The indoor and outdoor levels of benzene were often higher than the EU standard of 5μg/m³.

Endotoxin, ergosterol, muramic acid and fungal DNA in dust from schools in Johor Bahru, Malaysia--Associations with rhinitis and sick building syndrome (SBS) in junior high school students

This paper studied associations between ocular symptoms, rhinitis, throat and dermal symptoms, headache and fatigue in students by ethnicity and in relation to exposure to chemical microbial markers and fungal DNA in vacuumed dust in schools in Malaysia. A total of 462 students from 8 randomly selected secondary schools in Johor Bahru, Malaysia, participated (96% response rate). Dust was vacuumed from 32 classrooms and analysed for levels of five types of endotoxin as 3-hydroxy fatty acids (C10, C12, C14, C16 and C18 3-OH), muramic acid, ergosterol and five sequences of fungal DNA. Multiple logistic regression was applied. Totally 11.9% reported weekly ocular symptoms, 18.8% rhinitis, 15.6% throat and 11.1% dermal symptoms, 20.6% headache and 22.1% tiredness. Totally 21.1% reported pollen or furry pet allergy (atopy) and 22.0% parental asthma or allergy. Chinese students had less headache than Malay and Indian had less rhinitis and less tiredness than Malay. Parental asthma/allergy was a risk factor for ocular (odds ratio=3.79) and rhinitis symptoms (OR=3.48). Atopy was a risk factor for throat symptoms (OR=2.66), headache (OR=2.13) and tiredness (OR=2.02). There were positive associations between amount of fine dust in the dust samples and ocular symptoms (p<0.001) and rhinitis (p=0.006). There were positive associations between C14 3-OH and rhinitis (p<0.001) and between C18 3-OH and dermal symptoms (p=0.007). There were negative (protective) associations between levels of total endotoxin (LPS) (p=0.004) and levels of ergosterol (p=0.03) and rhinitis and between C12 3-OH and throat symptoms (p=0.004). In conclusion, the amount of fine dust in the classroom was associated with rhinitis and other SBS symptoms and improved cleaning of the schools is important. Endotoxin in the school dust seems to be mainly protective for rhinitis and throat symptoms but different types of endotoxin could have different effects. The ethnic differences in symptoms among the students deserve further attention.

Rhinitis, Ocular, Throat and Dermal Symptoms, Headache and Tiredness among Students in Schools from Johor Bahru, Malaysia: Associations with Fungal DNA and Mycotoxins in Classroom Dust

There are few studies on rhinitis and sick building syndrome (SBS) among students in tropical countries. We studied associations between levels of five fungal DNA sequences, two mycotoxins (sterigmatocystin and verrucarol) and cat allergen (Fel d 1) levels in schools and rhinitis and other weekly SBS symptoms in the students. Fungal DNA was measured by quantitative PCR and cat allergen by ELISA. Pupils (N = 462) from eight randomly selected schools in Johor Bahru, Malaysia participated (96%). Dust samples were collected by cotton swabs and Petri dishes exposed for one week. None of the schools had a mechanical ventilation system, but all classrooms had openable windows that were kept open during lectures and indoor CO2 levels were low (mean 492 ppm; range 380-690 ppm). Weekly nasal symptoms (rhinitis) (18.8%), ocular (11.6%), throat (11.1%), dermal symptoms, headache (20.6%) and tiredness (22.1%) were common. Total fungal DNA in swab samples was associated with rhinitis (p = 0.02), ocular symptoms (p = 0.009) and tiredness (p = 0.001). There were positive associations between Aspergillus versicolor DNA in Petri dish samples, ocular symptoms (p = 0.02) and tiredness (p = 0.001). The level of the mycotoxin verrucarol (produced by Stachybotrys chartarum) in swab samples was positively associated with tiredness (p = 0.04). Streptomyces DNA in swab samples (p = 0.03) and Petri dish samples (p = 0.03) were negatively associated with tiredness. In conclusion, total fungal contamination, measured as total fungal DNA) in the classrooms, Aspergillus versicolor and verrucarol can be risk factors for rhinitis and SBS symptoms among students in the tropical country Malaysia.

Particle size distribution and air pollution patterns in three urban environments in Xi'an, China

Three urban environments, office, apartment and restaurant, were selected to investigate the indoor and outdoor air quality as an inter-comparison in which CO2, particulate matter (PM) concentration and particle size ranging were concerned. In this investigation, CO2 level in the apartment (623 ppm) was the highest among the indoor environments and indoor levels were always higher than outdoor levels. The PM10 (333 µg/m(3)), PM2.5 (213 µg/m(3)), PM1 (148 µg/m(3)) concentrations in the office were 10-50% higher than in the restaurant and apartment, and the three indoor PM10 levels all exceeded the China standard of 150 µg/m(3). Particles ranging from 0.3 to 0.4 µm, 0.4 to 0.5 µm and 0.5 to 0.65 µm make largest contribution to particle mass in indoor air, and fine particles number concentrations were much higher than outdoor levels. Outdoor air pollution is mainly affected by heavy traffic, while indoor air pollution has various sources. Particularly, office environment was mainly affected by outdoor sources like soil dust and traffic emission; apartment particles were mainly caused by human activities; restaurant indoor air quality was affected by multiple sources among which cooking-generated fine particles and the human steam are main factors.

Sick Building Syndrome Among Junior High School Students in Japan in Relation to the Home and School Environment

Purpose:

There is an increasing concern about sick building syndrome (SBS), especially in Asia. The aim of this study is to investigate associations between SBS and the home, school environment and personal factors among Japanese junior high school students.

Methods:

We investigated students in four junior high schools in Hyogo in Kansai area, Japan. A questionnaire study was performed among students (n=1056), 12-15 years old. Temperature and relative air humidity was measured in the classrooms and dust was collected from the classroom floors and air and was analysed for cat and dog allergens. Associations were analysed by multi-level logistic regression.

Results:

Mucosal symptoms (45.4%), general symptoms (38.9%) and skin symptoms (22.6%) were common. Totally 8.8% reported cat allergy, 6.1% dog allergy, 6.0% mold allergy and 25.7% pollen allergy. Atopy, window pane condensation, floor dampness and odor at home and high relative air humidity in the classrooms were associated with SBS.

Conclusion:

The prevalence of SBS symptoms was high and associated with both home and school environment. Window pane condensation and floor dampness at home can increase the risk for SBS symptoms in students. Moreover high relative air humidity at school may increase the risk for SBS.

Personal and demographic factors and change of subjective indoor air quality reported by school children in relation to exposure at Swedish schools: a 2-year longitudinal study

This paper studies changes in subjective indoor air quality (SIAQ) among school children and relates these data to repeated exposure measurements during a two-year follow-up period. Data on SIAQ and demographic information were gathered by a questionnaire sent to 1476 primary and secondary school pupils in 39 randomly selected schools at baseline and after two years (follow-up). Exposure measurements were applied after questionnaire data were collected at baseline and follow-up in approximately 100 classrooms. The arithmetic mean values for baseline and follow-up were: for indoor air temperature 23.6°C and 21.8°C and for outdoor air flow rate 5.4 L/s and 7.9L/s. Older children, those with atopy at baseline, and those in larger schools reported impaired SIAQ during follow-up. Installation of new ventilation systems, higher personal air flow rate and air exchange rate, and better illumination were associated with improved SIAQ. Higher CO2 levels were associated with impaired SIAQ. In conclusion, sufficient ventilation and illumination in classrooms are essential for the perception of good indoor air quality.

Representativeness of shorter measurement sessions in long-term indoor air monitoring

Indoor air quality (IAQ) considerably influences health, comfort and the overall performance of people who spend most of their lives in confined spaces. For this reason, there is a strong need to develop methods for IAQ assessment. The fundamental issue in the quantitative determination of IAQ is the duration of measurements. Its inadequate choice may result in providing incorrect information and this potentially leads to wrong conclusions. The most complete information may be acquired through long-term monitoring. However it is typically perceived as impractical due to time and cost load. The aim of this study was to determine whether long-term monitoring can be adequately represented by a shorter measurement session. There were considered three measurable quantities: temperature, relative humidity and carbon dioxide concentration. They are commonly recognized as indicatives for IAQ and may be readily monitored. Scaled Kullback-Leibler divergence, also called relative entropy, was applied as a measure of data representativeness. We considered long-term monitoring in a range from 1 to 9 months. Based on our work, the representative data on CO2 concentration may be acquired while performing measurements during 20% of time dedicated to long-term monitoring. In the case of temperature and relative humidity the respective time demand was 50% of long-term monitoring. From our results, in indoor air monitoring strategies, there could be considered shorter measurement sessions, while still collecting data which are representative for long-term monitoring.

Influence of combined dust reducing carpet and compact air filtration unit on the indoor air quality of a classroom

Primary schools mostly rely on natural ventilation but also have an interest in affordable technology to improve indoor air quality (IAQ). Laboratory tests show promising results for dust reducing carpets and compact air filtration systems but there is no information available on the performance of these interventions in actual operating classrooms. An exploratory study was performed to evaluate a combination of the two systems in a primary school. Measurements of PM-10 and PM-2.5 were performed by filter sampling and aerosol spectrometry. Other IAQ parameters included black smoke (BS), volatile organic compounds (VOC), nitrogen dioxide (NO2) and formaldehyde. Both interventions were introduced in one classroom during one week, using another classroom as a reference. In a second week the interventions were moved to the other classroom, using the first as a reference (cross-over design). In three remaining weeks the classrooms were compared without interventions. Indoor IAQ parameters were compared to the corresponding outdoor parameters using the indoor/outdoor (I/O) ratio. When the classrooms were occupied (teaching hours) interventions resulted in 27-43% reductions of PM-10, PM-2.5 and BS values. During the weekends the systems reduced these levels by 51-87%. Evaluations using the change in I/O ratios gave comparable results. Levels of VOC, NO2 and formaldehyde were rather low and a contribution of the interventions to the improvement of these gas phase IAQ parameters was inconclusive.

A longitudinal study of sick building syndrome (SBS) among pupils in relation to SO2, NO2, O3 and PM10 in schools in China

There are fewer longitudinal studies from China on symptoms as described for the sick building syndrome (SBS). Here, we performed a two-year prospective study and investigated associations between environmental parameters such as room temperature, relative air humidity (RH), carbon dioxide (CO2), nitrogen dioxide (NO2), sulphur dioxide (SO2), ozone (O3), particulate matter (PM10), and health outcomes including prevalence, incidence and remission of SBS symptoms in junior high schools in Taiyuan, China. Totally 2134 pupils participated at baseline, and 1325 stayed in the same classrooms during the study period (2010-2012). The prevalence of mucosal symptoms, general symptoms and symptoms improved when away from school (school-related symptoms) was 22.7%, 20.4% and 39.2%, respectively, at baseline, and the prevalence increased during follow-up (P<0.001). At baseline, both indoor and outdoor SO2 were found positively associated with prevalence of school-related symptoms. Indoor O3 was shown to be positively associated with prevalence of skin symptoms. At follow-up, indoor PM10 was found to be positively associated with new onset of skin, mucosal and general symptoms. CO2 and RH were positively associated with new onset of mucosal, general and school-related symptoms. Outdoor SO2 was positively associated with new onset of skin symptoms, while outdoor NO2 was positively associated with new onset of skin, general and mucosal symptoms. Outdoor PM10 was found to be positively associated with new onset of skin, general and mucosal symptoms as well as school-related symptoms. In conclusion, symptoms as described for SBS were commonly found in school children in Taiyuan City, China, and increased during the two-year follow-up period. Environmental pollution, including PM10, SO2 and NO2, could increase the prevalence and incidence of SBS and decrease the remission rate. Moreover, parental asthma and allergy (heredity) and pollen or pet allergy (atopy) can be risk factors for SBS.

Sick building syndrome (SBS) and sick house syndrome (SHS) in relation to psychosocial stress at work in the Swedish workforce

PURPOSE

Medical symptoms called sick building syndrome (SBS) and sick house syndrome (SHS) are usually investigated separately: in this study, SBS and SHS were explored simultaneously. The significance of personal factors, perceptions of air quality, and psychosocial work situation in explaining SBS and SHS were investigated.

METHODS

A random sample of 1,000 subjects (20-65 year) received a postal questionnaire including questions on personal factors, medical symptoms, and the psychosocial demand-control-support model. The response rate was 70 % (n = 695), of which 532 were occupationally active.

RESULTS

In logistic regression models, atopy, poor air quality at work, and low social support, especially low supervisor support, were associated with both SBS and SHS when age, gender, smoking, and BMI were introduced. The general work-related symptoms (headache, tiredness, nausea, and sensation of a cold) were also related to low control over work.

CONCLUSIONS

The perception of poor physical environmental conditions is associated with common medical symptoms that are both work and home related. The associations between medical symptoms and poor air quality are still present, even when controlling for the psychosocial environment.

Dampness and moulds in workplace buildings: associations with incidence and remission of sick building syndrome (SBS) and biomarkers of inflammation in a 10 year follow-up study

There are few longitudinal studies on health effects of dampness and moulds in workplace buildings. We studied associations between dampness and indoor moulds in workplace buildings and selected biomarkers as well as incidence and remission of sick building syndrome (SBS). The study was based on a ten-year prospective study (1992-2002) in a random sample of adults (N=429) from the Uppsala part of the European Community Respiratory Health Survey (ECRHS). The 10-year incidence (onset) of general, mucosal, dermal symptoms and any symptom improved when away from the workplace (work-related symptoms) was 7.2%, 11.6%, 6.4% and 9.4% respectively. The 10-year remission of general, mucosal, dermal symptoms and work-related symptoms was 71.4%, 57.1%, 70.4% and 72.2% respectively. Signs of dampness in the floor construction in any workplace building during follow up (cumulative exposure) was associated with incidence of mucosal symptoms (OR=2.43). Cumulative exposure to moldy odor was associated with incidence of work-related symptoms (OR=2.69). Cumulative exposure to dampness or moulds was associated with decreased remission of work-related symptoms (OR=0.20 for water leakage, OR=0.17 for floor dampness, and OR=0.17 for visible indoor mould growth). Working in a building repaired because of dampness (repaired building) or mould was associated with decreased remission of work-related symptoms (OR=0.32). Any dampness or moulds at baseline in the workplace building was associated with increased bronchial responsiveness (BR) and higher levels of Eosinphilic Cationic Protein (ECP) in serum and Eosinophilic counts in blood at baseline. Cumulative exposure to dampness and moulds, and work in a repaired building, was associated with increased BR at follow-up. In general, dampness and moulds in the workplace building is associated with increased incidence and decreased remission of SBS, as well as increased bronchial responsiveness and eosinophilic inflammation.

A longitudinal study of sick building syndrome among pupils in relation to microbial components in dust in schools in China

There are few longitudinal studies on sick building syndrome (SBS), which include ocular, nasal, throat, and dermal symptoms, headache, and fatigue. We studied the associations between selected microbial components, fungal DNA, furry pet allergens, and incidence and remission of SBS symptoms in schools in Taiyuan, China. The study was based on a two-year prospective analysis in pupils (N=1143) in a random sample of schools in China. Settled dust in the classrooms was collected by vacuum cleaning and analyzed for lipopolysaccharide (LPS), muramic acid (MuA), and ergosterol (Erg). Airborne dust was collected in Petri dishes and analyzed for cat and dog allergens and fungal DNA. The relationship between the concentration of allergens and microbial compounds and new onset of SBS was analyzed by multi-level logistic regression. The prevalence of mucosal and general symptoms was 33% and 28%, respectively, at baseline, and increased during follow-up. At baseline, 27% reported at least one symptom that improved when away from school (school-related symptoms). New onset of mucosal symptoms was negatively associated with concentration of MuA, total LPS, and shorter lengths of 3-hydroxy fatty acids from LPS, C14, C16, and C18. Onset of general symptoms was negatively associated with C18 LPS. Onset of school-related symptoms was negatively associated with C16 LPS, but positively associated with total fungal DNA. In general, bacterial compounds (LPS and MuA) seem to protect against the development of mucosal and general symptoms, but fungal exposure measured as fungal DNA could increase the incidence of school-related symptoms.