Indoor air quality in Montréal area day-care centres, Canada

A participatory study of indoor environment quality in homes of children and youth in Kanehsatake First Nation

Indoor air quality is an important determinant for the health of children and youth, but the conditions within Indigenous communities are understudied. We collaborated with Kanehsatake First Nation in Quebec, Canada, to address this gap using a community-based participatory research approach. Levels of key indoor air indicators, including particulate matter (PM2.5), CO2, and relative humidity, were measured in 31 randomly selected households between June 2021 and January 2022. Questionnaires were administered remotely to collect information on housing conditions. Excessive humidity was common, with 52% of households having a relative humidity above 55%. The mean PM2.5 concentration was 21.0 (standard deviation 38.5) µg/m3, with higher mean levels observed in smoking compared to non-smoking households (36.1 µg/m3 and 10.1 µg/m3, respectively). The mean CO2 level in participating households was 881 ppm (standard deviation 256), with 30% (n = 9) of homes exceeding 1000 ppm. Flooding rates were high, with 55% of households reporting at least one past flood. One-third of houses were inadequately ventilated relative to occupancy, and over one-quarter reported needing major repairs. The results indicate the value and importance of characterizing the indoor environment in First Nations households and the viability of data collection through community-based participatory research in environmental health research.

Airborne Influenza Virus in Daycare Centers

In this study, we investigated the concentration of airborne influenza virus in daycare centers and influencing factors, such as common cold prevalence, air pollutants, and meteorological factors. A total of 209 air samples were collected from daycare centers in Kaohsiung and the influenza virus was analyzed using real-time quantitative polymerase chain reaction. Air pollutants and metrological factors were measured using real-time monitoring equipment. Winter had the highest positive rates of airborne influenza virus and the highest prevalence of the common cold, followed by summer and autumn. The concentration of CO was significantly positively correlated with airborne influenza virus. Daycare center A, with natural ventilation and air condition systems, had a higher concentration of airborne influenza A virus, airborne fungi, and airborne bacteria, as well as a higher prevalence of the common cold, than daycare center B, with a mechanical ventilation system and air purifiers, while the concentrations of CO2, CO, and UFPs in daycare center A were lower than those in daycare center B. We successfully detected airborne influenza virus in daycare centers, demonstrating that aerosol sampling for influenza can provide novel epidemiological insights and inform the management of influenza in daycare centers.

Indoor air quality in day-care centres: a global review

A healthy indoor environment is critical for children due to the severe effect of poor indoor air quality (IAQ) on their overall well-being. Day-care centres (DCCs) are important indoor microenvironments for children apart from their homes. Therefore, monitoring IAQ in this microenvironment is vital because of the vulnerability of the occupants. This review gives a global overview of the predominant indoor chemical pollutant levels monitored in DCCs, compares their concentration with available regulations for IAQ, evaluates the sources and health risk effects of chemical pollutants and proposes strategies for enhancing IAQ in DCCs. Thirty-seven (37) articles were used based on specific stated inclusion and exclusion criteria. Continents like Europe and Asia have the most published studies in indoor DCCs. The decreasing trend of pollutants examined in most studies include particulate matter > carbon dioxide > formaldehyde > carbon monoxide > total volatile organic compounds > volatile organic compounds > nitrogen dioxide > ozone > benzene > sulphur dioxide = radon. Particulate matter in the size and mass concentration range of PM₁₀ (0.116-1920.71 μg/m³) > PM_2.5 (0.279.2-260.74 μg/m³) was the most investigated pollutant. While nitrogen dioxide, radon and carbon monoxide were consistent with the existing national and international reference values for IAQ across the continents, exceedances occurred in other pollutants. The limited number of indoor chemical pollutant studies suggests the need for more comprehensive studies on IAQ in DCC globally. Further studies should highlight the availability of low-cost sensors and mobile analytical equipment that will promote affordable ground-level data accessibility.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11869-023-01320-5.

Geographic and social economic disparities in the risk of exposure to ambient air respiratory toxicants at Oklahoma licensed early care and education facilities

BACKGROUND

Early life exposures to hazardous air pollutants has been associated with adverse asthma-related outcomes. Neighborhood-level social and economic factors play an essential role in the distribution of hazardous air pollutants and children spend a substantial amount of time at early care and education (ECE) facilities. While the indoor air quality of these facilities has been described, particularly for criteria air pollutants such as volatile organic compounds and particulate matter, little is known about the ambient air quality of ECE facilities.

OBJECTIVES

We conducted a cross-sectional study to estimate the ambient air quality of Oklahoma licensed ECE facilities and to explore associations between ambient air quality and select geographic predictors.

METHODS

We estimated ambient air quality using the total respiratory hazard quotient from the National Air Toxics Assessment according to the geographical location of licensed Oklahoma ECE facilities (N = 3184). We then determined whether urban and rural ECE facilities' air respiratory toxicant exposure risk differed by ECE facilities' neighborhood-level social and economic inequities including: 1) racial-ethnic minority community, 2) neighborhood socioeconomic status, and 3) residential segregation.

RESULTS

Urban ECE facilities in Hispanic segregated counties were five times more likely to be at risk of high air respiratory exposure, adjusted for integrated urban counties (p < 0.0001, 95% CI [3.824, 7.699]). Rural ECE facilities in African American segregated counties were nine times more likely to be at risk of high air respiratory toxicant exposure, adjusted for integrated rural counties (p < 0.0001, 95% CI [5.641, 15.928]).

CONCLUSION

We found geographically and socially disparate patterns of higher exposures to ambient air respiratory toxicants at Oklahoma ECE facilities. Safer siting policies and interventions are needed to mitigate air respiratory toxicant exposures, which may help to reduce asthma control disparities and improve respiratory health outcomes in Oklahoma ECE facilities.

Ranking the environmental factors of indoor air quality of metropolitan independent coffee shops by Random Forests model

Independent coffee shops are the alternative workplaces for people working remotely from traditional offices but are not concerned about their indoor air quality (IAQ). This study aimed to rank the environmental factors in affecting the IAQ by Random Forests (RFs) models. The indoor environments and human activities of participated independent coffee shops were observed and recorded for 3 consecutive days including weekdays and weekend during the business hours. The multi-sized particulate matter (PM), particle-bound polycyclic aromatic hydrocarbons (p-PAHs), total volatile organic compounds (TVOCs), CO, CO₂, temperature and relative humidity were monitored. RFs models ranked the environmental factors. More than 20% of the 15-min average concentrations of PM₁₀, PM_2.5, and CO₂ exceeded the World Health Organization guidelines. Occupant density affected TVOCs, p-PAHs and CO₂ concentrations directly. Tobacco smoking dominated PM₁₀, PM_2.5, TVOCs and p-PAHs concentrations mostly. CO concentration was affected by roasting bean first and tobacco smoking secondly. The non-linear relationships between temperature and these pollutants illustrated the relative low concentrations happened at temperature between 22 and 24 °C. Tobacco smoking, roasting beans and occupant density are the observable activities to alert the IAQ change. Decreasing CO₂ and optimizing the room temperature could also be the surrogate parameters to assure the IAQ.

Assessment of ANN Algorithms for the Concentration Prediction of Indoor Air Pollutants in Child Daycare Centers

As the time spent by people indoors continues to significantly increase, much attention has been paid to indoor air quality. While many IAQ studies have been conducted through field measurements, the use of data-driven techniques such as machine learning has been increasingly used for the prediction of indoor air pollutants. For the present study, the concentrations of indoor air pollutants such as CO2, PM2.5, and VOCs in child daycare centers were predicted by using an artificial neural network model with three different training algorithms including Levenberg–Marquardt, Bayesian regularization, and Broyden–Fletcher–Goldfarb–Shanno quasi-Newton methods. For training and validation, data of indoor pollutants measured in child daycare facilities over a 1-month period were used. The results showed all the models produced a good performance for the prediction of indoor pollutants compared with the measured data. Among the models, the prediction by the LM model met the acceptable criteria of ASHRAE guideline 14 under all conditions. It was observed that the prediction performance decreased as the number of hidden layers increased. Moreover, the prediction performance was differed by the type of indoor pollutant. This was caused by patterns observed in the measured data. Considering the outcomes of the study, better prediction results can be obtained through the selection of suitable prediction models for time series data as well as the adjustment of training algorithms.

Cleaning Products Commonly Used in Oklahoma Family Child Care Homes: Implications for Respiratory Risk and Children's Health

Little is known about the cleaning products used by early care and education programs that contribute to childhood asthma, particularly in Oklahoma where rates of uncontrolled asthma are higher than national rates (60.0% vs. 50.3%, respectively). We conducted a cross-sectional study of cleaning products used by Oklahoma-licensed family child care homes (FCCHs) (n = 50) to characterize and identify potential respiratory-health risks associated with chemical contents. Overall, 386 chemicals were abstracted from the 132 reported products. Of these, 100 unique chemicals were identified. Four percent (4.2%) of providers used a product with a sensitizer that may cause allergy or asthma symptoms if inhaled and 35.4% used a product with an irritant that may cause irritation to the respiratory tract. Most (62.5%) reported using a product with a chemical that had a C=C double bond in its molecular structure that may make it highly reactive with other substances in the air and produce secondary air pollutants and 83.3% reported using a sodium hypochlorite containing product. Twenty-three percent reported products that contain carcinogens. Policy, educational, and technical assistance interventions are needed to promote the use of safer products and reduce respiratory and other health risks posed by chemicals in Oklahoma FCCHs.

Diurnal variation and potential sources of indoor formaldehyde at elementary school, high school and university in the Centre Val de Loire region of France

Formaldehyde (HCHO) is one of the abundant indoor pollutants and has been classified as a human carcinogen by the International Agency for Research on Cancer (IARC). Indoor HCHO at schools is particularly important due to the high occupancy density and the health effects on children. In this study, high time resolved measurement of formaldehyde concentration was conducted in the classrooms at elementary school, high school and university under normal students' activities in three different locations in the Region Centre Val de Loire-France. Indoor average formaldehyde concentrations at those three educational institutions were observed to be in the range 10.96-17.95 μg/m³, not exceeding the World Health Organization (WHO) guideline value of 100 μg/m³. As expected, ventilation was found playing an important role in the control of indoor formaldehyde concentration. After opening windows for 30 min, formaldehyde level decreased by ~25% and 38% in the classroom at the elementary school and the high school, respectively. In addition to the primary sources, the objective of this study was also to determine potential secondary sources of indoor formaldehyde in these schools by measuring the other volatile organic compounds (VOCs) present in the classrooms by a Proton Transfer Reaction Time-of-Flight Mass Spectrometry (PTR-ToF-MS). The measurements suggest that the release of residue from tobacco smokers is one of the major sources of indoor HCHO at the high school, which increases HCHO by ~55% averagely within 1 h. Moreover, the control experiments conducted in the university suggests that VOCs such as that released from cleaning products like terpenes, can contribute to the increase of indoor formaldehyde levels through chemical reactions with ozone. This study confirms simple recommendations to reduce the indoors HCHO concentration in schools: use ventilation systems, limit the emissions like cigarette smoke or cleaning products. It also points out that the secondary sources of formaldehyde must be also considered in the classroom.

Traffic exposure, air pollution and children's physical activity at early childhood education and care

BACKGROUND

A significant number of children attend Early Childhood Education and Care (ECEC). ECEC is an important environment and behaviour setting for young children. Time spent outdoors is positively associated with children's physical activity levels, yet increased time spent physically active outdoors may expose young children to traffic-related air pollution, particularly in ECEC centres located in high traffic areas.

METHODS

This study was part of the Play Spaces and Environments for Children's Physical Activity (PLAYCE) study, Perth, Western Australia. Data from 22 ECEC centres and 478 children were collected. Continuous measures of indoor and outdoor fine particulate matter (PM_2.5) were conducted for 48-72 h in each ECEC. Children wore ActiGraph GT3X + accelerometers to measure their physical activity at ECEC. The total length of high traffic roads within a 300m road network service area buffer around each ECEC was used to identify high and low traffic centres.

RESULTS

Outdoor PM_2.5 concentrations peaked in the afternoon (1pm, 2pm and 6pm) at ECEC centres. Outdoor and indoor PM_2.5 concentrations were significantly higher for centres located in high compared with low traffic areas (both p < 0.05). There was no significant association between a centre being located in a high or low traffic area and the time preschoolers spent outdoors or their physical activity levels.

DISCUSSION

Time periods when air pollution concentrations in ECECs are highest correspond with times when preschoolers are likely to be physically active outdoors. Children's potential exposure to traffic-related air pollutants is occurring during a period of rapid lung development. Given there is no evidence of a safe level of exposure to PM_2.5 or a threshold below which no adverse health effects occur, careful planning should be a consideration to avoid locating ECEC centres in high traffic areas.

Volatile Organic Compounds in Primary Schools in Ho Chi Minh City, Vietnam: Characterization and Health Risk Assessment

Limited information about exposure to volatile organic compounds (VOCs) in primary schools in Vietnam is available. In this study, we aimed to characterize indoor VOCs in four primary schools situated in Ho Chi Minh City, a metropolis in the south of Vietnam and assess health risks linked to the students’ exposure to VOCs. Indoor and outdoor air samples were collected in the schools and analyzed for volatile composition using gas chromatography coupled with mass spectrometry. Different classes of VOCs, including aromatic hydrocarbons, alkanes, aldehydes, esters, cyclic terpenes, and chlorinated hydrocarbons, were identified and quantified in classrooms of the schools. The results showed that the concentrations of the VOCs differed significantly among the schools and between ground-floor and first floor classrooms. In addition, VOC profiles differed considerably between air-conditioned and non-air-conditioned classrooms. Limonene, a compound associated with fragrance products, was the most abundant VOC, with the median (range) concentration of 26.12 (10.29, 50.08) μg/m3. The concentrations of the compounds examined in the study were in general found to be higher indoors compared with outdoors, signifying indoor emission sources. Potential harmful effects are expected as a result of exposure to benzene, ethylbenzene, naphthalene, 1,4-dichlorobenzene and tetrachloroethylene in the investigated schools. Further research is needed to fully assess the health risks to students, teachers, and staff in these educational environments.

Practical Impact of the COVID-19 Pandemic on Indoor Air Quality and Thermal Comfort in Kindergartens. A Case Study of Slovenia

The experimental monitoring of carbon dioxide concentration was carried out in kindergartens in Slovenia, together with indoor air temperature and relative humidity, before and during the COVID-19 pandemic. The aim of the research was to estimate the practical impact of the pandemic on indoor air quality and thermal comfort. The case study sample included buildings with different architectural typology, which are predominantly present in the building stock of Slovenia. The monitoring process lasted for 125 days before and during the COVID-19 pandemic. The results have shown a better indoor air quality in kindergartens during the pandemic, mostly due to ventilation protocols and almost imperceptibly changed indoor air temperature. The COVID-19 pandemic affected air quality in kindergarten classrooms in Slovenia by reducing the average carbon dioxide concentration when children were present in classrooms by 30%.

Exposure assessment in one central hospital: A multi-approach protocol to achieve an accurate risk characterization

The bioburden in a Hospital building originates not only from patients, visitors and staff, but is also disseminated by several indoor hospital characteristics and outdoor environmental sources. This study intends to assess the exposure to bioburden in one central Hospital with a multi-approach protocol using active and passive sampling methods. The microbial contamination was also characterized through molecular tools for toxigenic species, antifungal resistance and mycotoxins and endotoxins profile. Two cytotoxicity assays (MTT and resazurin) were conducted with two cell lines (Calu-3 and THP-1), and in vitro pro-inflammatory potential was assessed in THP-1 cell line. Out of the 15 sampling locations 33.3% did not comply with Portuguese legislation regarding bacterial contamination, whereas concerning fungal contamination 60% presented I/O > 1. Toxigenic fungal species were observed in 27% of the sampled rooms (4 out of 15) and qPCR analysis successfully amplified DNA from the Aspergillus sections Flavi and Fumigati, although mycotoxins were not detected. Growth of distinct fungal species was observed on Sabouraud dextrose agar with triazole drugs, such as Aspergillus section Versicolores on 1 mg/L VORI. The highest concentrations of endotoxins were found in settled dust samples and ranged from 5.72 to 23.0 EU.mg^-1. While a considerable cytotoxic effect (cell viability < 30%) was observed in one HVAC filter sample with Calu-3 cell line, it was not observed with THP-1 cell line. In air samples a medium cytotoxic effect (61-68% cell viability) was observed in 3 out of 15 samples. The cytokine responses produced a more potent average cell response (46.8 ± 12.3 ρg/mL IL-1β; 90.8 ± 58.5 ρg/mL TNF-α) on passive samples than air samples (25.5 ± 5.2 ρg/mL IL-1β and of 19.4 ± 5.2 ρg/mL TNF-α). A multi-approach regarding parameters to assess, sampling and analysis methods should be followed to characterize the biorburden in the Hospital indoor environment. This study supports the importance of considering exposure to complex mixtures in indoor environments.

Exposure and risk assessment of volatile organic compounds and airborne phthalates in Singapore's Child Care Centers

Infants and children under 6 years old spend most of daily time in Child Care Centers (CCCs), especially in the tropical regions like Singapore. Environmental exposure and associated risk during this early critical developmental stage is of great public concern. In this study, seven representative volatile organic compounds (VOCs) and five typical phthalates were analyzed in the indoor and outdoor air samples collected from 32 Singapore CCCs. The median of total VOC and phthalate concentration in indoor air was 19.03 and 5.41 μg m^-3; respectively. For both indoors and outdoors environment, benzene, toluene and xylene were the dominant VOC contributors (more than 68%). For indoor air phthalates, di(2-ethylhexyl) phthalate and di-butyl phthalate (DBP) accounts for 60-76%. The level of both VOCs and phthalates in indoor environment was significantly higher than that in outdoor, with an average indoor/outdoor ratio of 1.24 and 1.45; respectively. A strong correlation (r > 0.50, p < 0.05) was observed between indoor and outdoor air compounds. VOC and phthalate levels have no significant difference between CCCs with split-unit and centrally ventilated air conditioners. Monte Carlo simulation was used to estimate exposure uncertainty and variability for the risk assessment. Overall, the concentrations of VOC were below the healthy reference values from either EPA Integrated Risk Information System (IRIS) or Singapore guideline. However, similar to other countries' report, benzene, DBP, ethylbenzene and naphthalene were at levels that could exceed the stringent standards such as Office of Environmental Health Hazard Assessment (OEHHA) cancer and reproductive health-based benchmarks.

Exposure profiles, seasonal variation and health risk assessment of BTEX in indoor air of homes at different microenvironments of a terai province of northern India

BTEX are known for their ability to deteriorate human health. A monitoring study was conducted at Gorakhpur, for a span of one year. BTEX were sampled by drawing air through activated charcoal tubes, using a low flow SKC model 220 pump. Samples were extracted with CS₂ followed by subjecting the aromatic fraction to GC-FID. The mean concentration of BTEX was highest at agricultural (54.3 μg m^-3) followed by industrial (18.2 μg m^-3), roadside (12.3 μg m^-3) and residential site (6.1 μg m^-3). Toluene levels were higher than benzene at all the sites except agricultural site, where benzene concentration exceeded toluene. Seasonal variation showed highest BTEX concentration during winters (32.56 μg m^-3) followed by monsoon (19.90 μg m^-3) and summers (14.44 μg m^-3). At each site, BTEX levels increased with decrease in temperature. Benzene and toluene levels were plotted against indoor temperature, which revealed a significant linear correlation (p < 0.001) for each plot. BTEX concentrations were compared between different sites using Student's t and Mann Whitney U tests. Value of integrated lifetime cancer risk (ILTCR) was higher than 10^-6 for benzene at all the sites, while for ethylbenzene, it was only higher at agricultural site. Cumulative hazard index (HI) was lower than 1.0 at all the sites.

VOC exposures in California early childhood education environments

Little information exists about exposures to volatile organic compounds (VOCs) in early childhood education (ECE) environments. We measured 38 VOCs in single-day air samples collected in 2010-2011 from 34 ECE facilities serving California children and evaluated potential health risks. We also examined unknown peaks in the GC/MS chromatographs for indoor samples and identified 119 of these compounds using mass spectral libraries. VOCs found in cleaning and personal care products had the highest indoor concentrations (d-limonene and decamethylcyclopentasiloxane [D5] medians: 33.1 and 51.4 μg/m³, respectively). If reflective of long-term averages, child exposures to benzene, chloroform, ethylbenzene, and naphthalene exceeded age-adjusted "safe harbor levels" based on California's Proposition 65 guidelines (10^-5 lifetime cancer risk) in 71%, 38%, 56%, and 97% of facilities, respectively. For VOCs without health benchmarks, we used information from toxicological databases and quantitative structure-activity relationship models to assess potential health concerns and identified 12 VOCs that warrant additional evaluation, including a number of terpenes and fragrance compounds. While VOC levels in ECE facilities resemble those in school and home environments, mitigation strategies are warranted to reduce exposures. More research is needed to identify sources and health risks of many VOCs and to support outreach to improve air quality in ECE facilities.

Formaldehyde and carbon dioxide air concentrations and their relationship with indoor environmental factors in daycare centers

The aim of this study was to measure the air concentrations of carbon dioxide (CO₂) and formaldehyde (HCHO) in daycare centers to determine relevant influencing factors, including temperature, relative humidity (RH), type of facility, number of children, type of ventilation system, ventilation time, and air cleaning system. The authors measured HCHO, CO₂, temperature, and RH in the center of classrooms in 289 daycare centers. Spearman's correlation and Mann-Whitney analyses were used to examine the relationships and differences in HCHO and CO₂ for varying temperatures, RH values, and categorical indoor environmental factors. There were no significant differences in the HCHO and CO₂ air concentrations with varying numbers of children, ventilation times, or ventilation and air cleaning system types. However, both the HCHO and CO₂ air concentrations were significantly different for varying RH values, which were divided into five categories (p < 0.001). Only the HCHO air concentrations were significantly different for varying temperatures, which were divided into five categories (p < 0.001). Significant correlations were found between HCHO air concentrations and the temperature (r = 0.35, p < 0.0001), RH (r = 0.51, p < 0.0001), and CO₂ (r = 0.36, p < 0.0001). The study results support maintaining an appropriate temperature and RH range for reducing airborne HCHO in daycare centers. Further research is needed to elucidate the precise mechanisms responsible for the relationships observed in this study.

IMPLICATIONS

Data from 289 daycare centers in Seoul, South Korea, indicate that HCHO concentrations show a positive correlation with indoor temperature and relative humidity. This indicates that keeping temperatures low will help keep HCHO concentrations low, by both a direct and an indirect effect, since low temperatures also cause low relative humidity.

Formaldehyde and acetaldehyde exposure and risk characterization in California early childhood education environments

Little information is available about air quality in early childhood education (ECE) facilities. We collected single-day air samples in 2010-2011 from 40 ECE facilities serving children ≤6 years old in California and applied new methods to evaluate cancer risk in young children. Formaldehyde and acetaldehyde were detected in 100% of samples. The median (max) indoor formaldehyde and acetaldehyde levels (μg/m³ ) were 17.8 (48.8) and 7.5 (23.3), respectively, and were comparable to other California schools and homes. Formaldehyde and acetaldehyde concentrations were inversely associated with air exchange rates (Pearson r = -0.54 and -0.63, respectively; P < 0.001). The buildings and furnishings were generally >5 years old, suggesting other indoor sources. Formaldehyde levels exceeded California 8-h and chronic Reference Exposure Levels (both 9 μg/m³ ) for non-cancer effects in 87.5% of facilities. Acetaldehyde levels exceeded the U.S. EPA Reference Concentration in 30% of facilities. If reflective of long-term averages, estimated exposures would exceed age-adjusted 'safe harbor levels' based on California's Proposition 65 guidelines (10^-5 lifetime cancer risk). Additional research is needed to identify sources of formaldehyde and acetaldehyde and strategies to reduce indoor air levels. The impact of recent California and proposed U.S. EPA regulations to reduce formaldehyde levels in future construction should be assessed.

Effect of indoor air quality of day care centers in children with different predisposition for asthma

BACKGROUND

Scarce information is available about the relationships between indoor air quality (IAQ) at day care centers (DCC), the estimated predisposition for asthma, and the actual wheezing susceptibility.

METHODS

In the Phase II of ENVIRH study, 19 DCC were recruited after cluster analysis. Children were evaluated firstly using the ISAAC questionnaire and later by a follow-up questionnaire about recent wheezing. A positive asthma predictive index (API) was considered as predisposition for asthma. Every DCC was audited for IAQ and monitored for chemical and biologic contaminants.

RESULTS

We included 1191 children, with a median age of 43 (P25 -P75 : 25-58) months. Considering the overall sample, in the first questionnaire, associations were found between CO2 concentration (increments of 200 ppm) and diagnosis of asthma (OR: 1.10; 95% CI: 1.00-1.20). Each increment of 100 μg/m(3) of total volatile organic compounds (TVOC) and 1 μg of Der p1/g of dust were associated with wheezing in the previous 12 months (OR: 1.06; 95% CI: 1.01-1.11 and OR: 1.06; 95% CI: 0.99-1.12, respectively). In the follow-up questionnaire, TVOC were again associated with wheezing (OR: 1.05; 95% CI: 1.00-1.11). Children exposed to fungal concentration above the 75th percentile had also higher odds of wheezing at follow-up. TVOC were associated with wheezing in children with either negative or positive API.

CONCLUSIONS

IAQ in DCC seems to be associated with wheezing, in children with and without predisposition for asthma.

Ventilation in day care centers and sick leave among nursery children

Several studies have reported poor indoor air quality (IAQ) in day care centers (DCCs), and other studies have shown that children attending them have an increased risk of respiratory and gastrointestinal infections. The aim of this study was to investigate whether there is an association between ventilation in DCCs and sick leave among nursery children. Data on child sick leave within an 11-week period were obtained for 635 children attending 20 DCCs. Ventilation measurements included three proxies of ventilation: air exchange rate (ACR) measured with the decay method, ACR measured by the perfluorocarbon tracer gas (PFT) method, and CO2 concentration measured over a 1-week period. All but two DCCs had balanced mechanical ventilation system, which could explain the low CO2 levels measured. The mean concentration of CO2 was 643 ppm, exceeding 1000 ppm in only one DCC. A statistically significant inverse relationship between the number of sick days and ACR measured with the decay method was found for crude and adjusted analysis, with a 12% decrease in number of sick days per hour increase in ACR measured with the decay method. This study suggests a relationship between sick leave among nursery children and ventilation in DCCs, as measured with the decay method.

Gaseous pollutants on rural and urban nursery schools in Northern Portugal

Indoor air quality in nursery schools is different from other schools and this has been largely ignored, particularly in rural areas. Urban and rural nursery schools have different environmental characteristics whose knowledge needs improvement. Thus, this study aimed to evaluate continuously the concentrations of CO2, CO, NO2, O3, CH2O and total VOC in three rural nursery schools and one urban, being the only one comparing urban and rural nurseries with continuous measurements, thus considering occupation and non-occupation periods. Regarding CO2, urban nursery recorded higher concentrations (739-2328 mg m(-3)) than rural nurseries (653-1078 mg m(-3)). The influence of outdoor air was the main source of CO, NO2 and O3 indoor concentrations. CO and NO2 concentrations were higher in the urban nursery and O3 concentrations were higher in rural ones. CH2O and TVOC concentrations seemed to be related to internal sources, such as furniture and flooring finishing and cleaning products.

Children's exposure to indoor air in urban nurseries--Part II: Gaseous pollutants' assessment

This study, Part II of the larger study "Children's exposure to indoor air in urban nurseries", aimed to: (i) evaluate nursery schools' indoor concentrations of several air pollutants in class and lunch rooms; and (ii) analyse them according to guidelines and references. Indoor continuous measurements were performed, and outdoor concentrations were obtained to determine indoor/outdoor ratios. The influence of outdoor air seemed to be determinant on carbon monoxide (CO), nitrogen dioxide (NO2) and ozone (O3) indoor concentrations. The peak concentrations of formaldehyde and volatile organic compounds (VOC) registered (highest concentrations of 204 and 2320 µg m(-3) respectively), indicated the presence of specific indoor sources of these pollutants, namely materials emitting formaldehyde and products emitting VOC associated to cleaning and children's specific activities (like paints and glues). For formaldehyde, baseline constant concentrations along the day were also found in some of the studied rooms, which enhances the importance of detailing the study of children's short and long-term exposure to this indoor air pollutant. While CO, NO2 and O3 never exceeded the national and international reference values for IAQ and health protection, exceedances were found for formaldehyde and VOC. For this reason, a health risk assessment approach could be interesting for future research to assess children's health risks of exposure to formaldehyde and to VOC concentrations in nursery schools. Changing cleaning schedules and materials emitting formaldehyde, and more efficient ventilation while using products emitting VOC, with the correct amount and distribution of fresh air, would decrease children's exposure.

Children's exposure to indoor air in urban nurseries-part I: CO₂ and comfort assessment

Indoor air quality (IAQ) in nurseries is an emerging case-study. Thus, this study, as the Part I of the larger study "Children's exposure to indoor air in urban nurseries", aimed to: i) evaluate nurseries' indoor concentrations of carbon dioxide (CO2), a global IAQ indicator, in class and lunch rooms; ii) assess indoor comfort parameters-temperature (T) and relative humidity (RH); and iii) analyse them according to guidelines and references for IAQ, comfort and children's health. Indoor continuous measurements were performed. Non-compliances with guidelines were found in comfort parameters, which could cause discomfort situations and also microbial proliferation. Exceedances in CO2 concentrations were also found and they were caused by poor ventilation and high classroom occupation. More efficient ventilation and control of comfort parameters, as well as to reduce occupation by reviewing Portuguese legislation on that matter, would certainly improve IAQ and comfort in nurseries and consequently safeguard children's health.

CO(2) concentration in day care centres is related to wheezing in attending children

Poor ventilation at day care centres (DCCs) was already reported, although its effects on attending children are not clear. This study aimed to evaluate the association between wheezing in children and indoor CO2 (a ventilation surrogate marker) in DCC and to identify behaviours and building characteristics potentially related to CO2. In phase I, 45 DCCs from Lisbon and Oporto (Portugal) were selected through a proportional stratified random sampling. In phase II, 3 months later, 19 DCCs were further reassessed after cluster analysis for the greatest difference comparison. In both phases, children's respiratory health was assessed by ISAAC-derived questionnaires. Indoor CO2 concentrations and building characteristics of the DCC were evaluated in both phases, using complementary methods. Mixed effect models were used to analyze the data. In phase I, which included 3,186 children (mean age 3.1 ± 1.5 years), indoor CO2 concentration in the DCC rooms was associated with reported wheezing in the past 12 months (27.5 %) (adjusted odds ratio (OR) for each increase of 200 ppm 1.04, 95 % CI 1:01 to 1:07). In phase II, the association in the subsample of 1,196 children seen in 19 out of the initial 45 DCCs was not significant (adjusted OR 1.02, 95 % CI 0.96 to 1.08). Indoor CO2 concentration was inversely associated with the practices of opening windows and internal doors and with higher wind velocity. A positive trend was observed between CO2 and prevalence of reported asthma (4.7 %).

CONCLUSION

Improved ventilation is needed to achieve a healthier indoor environment in DCC.

Formaldehyde: a chemical of concern in the vicinity of MBT plants of municipal solid waste

The mechanical-biological treatment (MBT) of municipal solid waste (MSW) has a number of advantages in comparison to other MSW management possibilities. However, adverse health effects related to this practice are not well known yet, as a varied typology of microbiological and chemical agents may be generated and released. In 2010, we initiated an environmental monitoring program to control air levels of volatile organic compounds (VOCs) and microbiological pollutants near an MBT plant in Montcada i Reixac (Catalonia, Spain). In order to assess any temporal and seasonal trends, four 6-monthly campaigns were performed. Important fluctuations were observed in the levels of different biological indicators (total and Gram-negative bacteria, fungi grown at 25 °C and 37 °C, and more specifically, Aspergillus fumigatus). Although overall bioaerosols concentrations were rather low, a certain increase in the mean values of bacteria and fungi was observed in summer. In contrast, higher concentrations of VOCs were found in winter, with the only exception of formaldehyde. Interestingly, although this compound was not detected in one of the sampling campaigns, current airborne levels of formaldehyde were higher than those previously reported in urban areas across Europe. Furthermore, the non-carcinogenic risks (Hazard Quotient), particularly in winter, as well as the cancer risks associated with the inhalation of VOCs, exceeded the threshold values (1 and 10(-5), respectively), reaffirming the need of continuing with the monitoring program, with special emphasis on formaldehyde, a carcinogenic/mutagenic substance.

Environmental and ventilation assessment in Child Day Care Centers in Porto: the ENVIRH Project

Children attending day care centers (CDCC) have been reported to be more prone to infectious diseases when compared with those cared for at home, and are exposed to conditions that may increase the risk of allergies and asthma. Several studies revealed that consequences of poor ventilation conditions include high levels of carbon dioxide (CO2) and many other indoor pollutants commonly detected in schools. Nine child day care centers were selected randomly to participate in this study. Fifty-two classrooms were assessed for chemical, biological, physical, and allergen parameters in spring and winter seasons in these nine CDCC located in Porto, Portugal. Outdoor measurements were also conducted for comparison. Our results indicated that (i) particulate matter (PM10) median levels were above the national reference levels, both by classroom type and by season; (ii) TVOC kindergarten peak values may raise some concern; (iii) CO2 was present at high median and maximum levels during spring and winter assessment in both nurseries and kindergartens classrooms; (iv) total bacteria concentrations were 57- and 52-fold higher in the nursery and kindergarten than outdoors, respectively, for the spring season; (v) winter and spring median predicted mean vote (PMV) indices were between "neutral" (0) and "slightly cool" (≤ -1) in the thermal sensation scale for comfort situations (-2 to 2) for both types of classrooms; (vi) there were significant differences for both PMV and predicted percentage of dissatisfied (PPD) indices by season; and (vii) CO2, total bacteria, and gram-negative bacteria were associated with low airflow rates. These data will help to evaluate the effectiveness of current building operation practices in child day care centers regarding indoor air quality and respiratory health.