Until rather recently, the emphasis on air quality evaluation has been centred upon the outdoor environment, namely on studies regarding behaviour, effects and outdoor air pollutants prediction [1
] and it has been reported that outdoor pollution, specifically nitrogen dioxide (NO2
), particulate matter with an aerodynamic diameter equal or smaller than 10
) and ozone (O3
), causes an increase on asthma prevalence and also on its severity, having worst effects on children [6
]. It is now known that IAP likely has equal or even greater impact on children’s health when compared to that of outdoor pollutants. This occurs because time spent indoor is usually higher than time spent outdoor; also, there is a great variety of indoor sources, that include outdoor and specific indoor sources associated with formaldehyde and volatile organic compounds (VOC) emissions, leading frequently to higher concentration than outdoor [12
]. The World Health Organization (WHO) has assessed the contribution of a range of risk factors to the burden of disease and revealed IAP as the 8th most important risk factor and responsible for 2.7% of the global burden of disease [15
]. Exposure to IAP has been linked to a variety of health effects, including respiratory health problems and exacerbation of childhood asthma [16
Children are highly vulnerable to air pollution effects for a variety of reasons, being considered a risk group [17
]. Evaluating the risk of developing childhood asthma is one of the four priority issues identified by the European Community, according to the European Union Environment and Health Action Plan [19
]. Additionally, prevention of the health effects of poor indoor air quality is needed in all regions of the world [15
]. Current evidence on the effectiveness of different interventions is insufficient for providing clear guidance to decision-makers on suitable strategies to reduce the health effects caused by IAP [15
Accordingly, indoor air quality at schools has attracted increasing public attention in recent years because children spent most of their time at school (8–10
h per day, of which 2–3
h are spent outdoors) [19
]. Building materials can release a wide range of pollutants, such as formaldehyde from chipboard and hydrocarbons from paints, cleaners and furnishings [15
]. Frequently, pollutants from indoor sources may build up to appreciable levels because of the slowness of air exchange.
Several studies have demonstrated associations between exposure to IAP and exacerbation of childhood asthma [12
]. Nevertheless, uncertainty remains in the causative role of IAP in asthma, but evidence is suggesting that several air pollutants may contribute to both exacerbation and development of asthma.
IAP constitutes a complex case for risk assessment due to a wide number of reasons such as the variety of pollutants, exposure levels, cultural habits, building stock and climate. Also comparison between study areas is a difficult issue because of the different methodologies applied for both pollutant measurements and asthma identification. Generally, IAP studies were performed for specific pollutants and areas, thus not considering all of the most important indoor pollutants and with no possible way to use for comparison with other areas. Additionally, a great uncertainty still remains in the exposure patterns, thus models have been developed to predict the emissions and distribution patterns of pollutants. Such models are essential for the development of indoor exposure and risk assessment [22
]. However, no general model has yet been well established [24
]. Another difficulty remains in the study design; generally, studies investigating the respiratory health effects of IAP on children show either the short or the long-term effects, thus evaluating only prevalence or incidence or exacerbation and usually only in a determined age group [24
As far as our knowledge goes, only 4 projects were approved in Portugal concerning indoor air quality and health effects on children. These studies were lacking the evaluation of some important indoor air pollutants, each study only evaluated one strict age group, study design was cross-sectional, evaluating only asthma prevalence or only asthma exacerbation and comparison between regions with different air pollution characteristics was not considered [25
INAIRCHILD aims to reduce these lacks, going further on the subject by: i) characterizing in detail the indoor air quality both in nurseries and primary schools, considering all the important indoor air pollutants (carbon monoxide (CO), carbon dioxide (CO2
, VOC, formaldehyde, radon, bacteria, including legionella when necessary) and fungi; ii) understanding and comparing simultaneously the effects of environment on asthma at different age groups (children will have from 1–10
years old); iii) performing a longitudinal study, allowing the evaluation of asthma prevalence, incidence and, if possible, exacerbation; iv) comparing regions of different air pollution characteristics, namely urban and rural areas in terms of indoor pollution and asthma prevalence, incidence and, if possible, exacerbation; and v) contributing to a better supported development of preventive measures.
Globally, the expected results of the project are: i) to identify the pollutants that eventually increase the prevalence and incidence of childhood asthma and exacerbate respiratory symptoms, which will allow developing strategies to reduce the levels of those pollutants aiming the reduction of the incidence rate of childhood asthma; ii) to support directly and indirectly the environmental education, namely through the distribution of flyers, and through the participation of scholar communities (including parents) on the study and on promoting strategies to reduce the levels of indoor pollution and thus the impact on childhood health; and iii) dissemination of the results obtained to the scientific community and the communication of the results to the competent political authorities allowing an eventual revision and adaptation of standards to effectively protect children health.