Environmental quality in primary schools and related health effects in children. An overview of assessments conducted in the Northern Portugal
Graphical abstract
Introduction
There is irrefutable evidence that exposure to air pollution, occurring in indoor and outdoor environments, constitutes an important contributing factor for an increased risk of premature death and development of a variety of adverse health outcomes [1], [2]. Thus, air pollution is a priority public health issue that needs to be addressed globally. Although exposure to high levels of air pollutants is likely to represent important risks to health at all ages, children are particularly vulnerable due to their physiological, behavioral and social specificities. Compared to adults, children are more susceptible to toxic damages induced by air pollution due to their immature respiratory and immune systems. Children are also prone to higher intake of hazardous substances from the environment due to their higher daily inhalation rate, larger lung surface area per kilogram of body weight and hand-to-mouth behavior (more frequent in early years) [3], [4], [5], [6]. As school-age children spend approximately a third of their day in school educational environments are considered to be major contributors of total exposure during childhood. This is supported by growing body of evidence that has demonstrated that poor indoor air quality (IAQ) conditions are very likely to occur in classrooms [7], [8]. Moreover, associations between poor quality of the environment in schools and increased risk of development of diseases, including respiratory and allergic symptoms, and compromised academic performance in children have been well-documented [8], [9].
Among the existing studies in the field, the SINPHONIE project – Schools Indoor Pollution and Health Observatory Network in Europe – that collected information on IAQ in school buildings and related health data for school-age children across 23 European countries is particularly relevant. SINPHONIE provided robust evidence for the implementation of measures to mitigate preventable environmental harm in public school buildings [10], [11]. The more recently published outcomes from SINPHONIE also show the existence of significant variabilities in IAQ determinants among the established geographic clusters – Northern, Western, Central and Southern Europe [8]. In fact, the putative environmental hazards associated with schools and other indoor settings are reported to hugely fluctuate according to specific local issues [12], namely those related to local ambient air pollution patterns, construction and ventilation typologies, climate characteristics and consumption trends. These observations, along with the fact that the SINPHONIE protocol was based on a limited number of surveyed buildings per country (e.g. in Portugal only 3 schools were assessed), suggest that more comprehensive information on the overall IAQ and its impact on children’s health should be provided at local level. This would contribute to the design of effective evidence-based policies and implementation of preventive measures adjusted to local needs.
Growing urbanization has important implications on environmental and demographic changes [13], namely on environmental degradation, land changes, and loss of green areas [14]. Urban green spaces have been associated with sustainable and healthy urban development [14]. Moreover, previous studies suggested that exposure to green spaces may influence human health and wellbeing through many different pathways, namely through decreasing the levels of ambient air pollutants, thereby contributing to reduce the risk of environment-related adverse health effects [15], [16]. Some authors reported a negative association between urban natural areas and asthma, stating the existence of a protective effect of green areas on respiratory diseases [17], [18], [19]. However, the existing studies on greenness and respiratory outcomes are still inconsistent [20]. Ruokolainen et al. also reported an inverse association between higher exposure to natural areas, including forest and agricultural areas, and the risk of atopic sensitization among children and adolescents, addressing to the biodiversity hypothesis [21].
With all the above in mind, an extensive sequential program of studies that aimed to tackle in a comprehensive way the issues related to the quality of the environment in public primary schools was conducted in Porto Municipality. First, almost concurrently with the SINPHONIE project, (2011–2013), a study conducted in 20 Portuguese primary schools demonstrated that indoor air pollutants, some even at low exposure levels, were related with the development of respiratory symptoms in children [22], [23], [24]. Following, the ARIA project on How Indoor Air Quality Affect Children Allergies and Asthma was assembled as a more comprehensive and independent study aiming to deepen the knowledge of school environment-related impacts on children’s health. Compared to the previous assessment plan, ARIA study was innovative in: i) extending the subset of IAQ parameters assessed in the classrooms in the 2014/2015 heating season period; ii) conducting more comprehensive clinical assessments in school-age children; and iii) including the analysis of the influence of the characteristics (built and green areas, and species richness) of the environment surrounding the primary schools for children’s health. For instance, ARIA was designed to improve the understanding of the effects of exposure to schools’ indoor air on children’s health while also considering the contribution of the environment surrounding the school buildings.
This work intends to present a holistic view of the results obtained in the ARIA project. Specifically, the complete dataset on IAQ collected in ARIA classrooms will be comprehensively explored for the first time. These results are presented along with the main outcomes from published evidence on the relevant characteristics of the environment surrounding schools, and also on health status of children.
Section snippets
Description of the ARIA study design and of surveyed primary schools
The multi perspective assessment plan implemented in ARIA included a variety of data collection and analysis methods to: i) comprehensively assess IAQ in schools; ii) characterize urban green spaces and species richness in schools’ surroundings; iii) evaluate health endpoints in children; and iv) investigate the existence of associations between the environmental indicators and health outcomes. This cross-sectional study involved 20 out of 53 public primary schools existing at the time of the
Indoor environmental quality in the primary schools surveyed
The information collected using the study checklist applied during the walkthrough inspection, aiming to gather information on the characteristics of school buildings and classrooms surveyed are presented in the Supplementary material (Tables S1 and S2). The levels of environmental parameters assessed in this work showed a considerable fluctuation across the sample of surveyed classrooms. This is shown in Table 2 and will be fully described below.
Health determinants in the built environment
Children exposed to higher fungal diversity were found to be at a lower risk of developing allergic sensitization (OR [95% CI] = 0.60 [0.40; 0.92]), but not asthma [29]. In contrast, higher exposure to bacteria endotoxins and Penicillium spp in primary schools’ classrooms was associated with a higher risk of allergic sensitization in children (OR [95% CI] = 1.40 [95% CI: 0.99; 1.99] and 1.68 [1.18; 2.40], respectively). Hence, the microbial quality in the classroom environment seems of utmost
Study limitations and strengths
As far as we know this is the largest study to comprehensively assess the quality of environment in educational settings and its impact on school-age children covering the harmonized assessment of a wide subset of environmental and health related parameters. As some significant associations were established between the characteristics of the buildings/classrooms and pollutant levels, the findings presented here could be also, at least in some extent, extrapolated to the Portuguese primary
Conclusion
The ARIA project substantially expanded existing knowledge on the role of indoor environment and neighborhoods of schools as determinants of health detriments in children and on identifying strategies for health risk mitigation through the implementation of a harmonized comprehensive and multi-perspective assessment plan. Overall, results from ARIA showed that failure to address poor ventilation and indoor air quality in a considerable number of schools can result in poor quality of
CRediT authorship contribution statement
Marta Fonseca Gabriel: Data curation, Formal analysis, Visualization, Writing - original draft. Inês Paciência: Data curation, Formal analysis, Visualization, Investigation, Writing - original draft. Fátima Felgueiras: Data curation, Formal analysis, Visualization, Investigation, Writing - review & editing. João Cavaleiro Rufo: Data curation, Formal analysis, Visualization, Investigation, Writing - original draft. Francisca Castro Mendes: Formal analysis, Investigation, Writing - original
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
This study was performed in the framework of the ARIA project financed by Fundação para a Ciência e Tecnologia (PTDC/DTP-SPA/1522/2012, FCOMP-01-0124-FEDER-028709). The authors also gratefully acknowledge all participants and families involved in the project.
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