Seite - 122 - in Biodiversity and Health in the Face of Climate Change

122 Keywords Green space · Built environment · Biodiversity · Child health · Child development · Biophilia Highlights • Pre- and postnatal periods are important windows of vulnerability. • Contact with green spaces is associated with improved pregnancy outcomes. • Green spaces are beneficial for child brain (cognitive and behavioural) development. • There is inconsistent evidence on the association with respiratory and allergic conditions. • There is inconsistent evidence on the association with obesity and physical activity. 6.1 Potential Mechanisms Mechanisms through which green spaces could exert their health benefits for foe- tuses and children are yet to be established. However, stress reduction; increase in social contacts and cohesion; enhanced physical activity; mitigation of urban- related environmental hazards such as air pollution, noise and heat; and enrichment of environmental microbiota have been suggested to play a role. The available evi- dence is still limited. Of the aforementioned mechanisms, mitigation of air pollution has been investigated the most. A study of 52 pregnant women in Barcelona, Spain, reported that higher residential surrounding greenness was associated with lower personal exposure to particulate air pollution, as measured by personal monitors (Dadvand et  al. 2012). Another study reported that higher greenness within and sur- rounding 39 schools in Barcelona, Spain, was associated with lower indoor (e.g. classroom) and outdoor (e.g. yard) levels of traffic-related air pollution in these schools (Dadvand et  al. 2015b). A second study of schoolchildren from these schools showed that 20–65% of the associations between school greenness and cog- nitive development could be explained by lower air pollution levels (Dadvand et  al. 2015a). However, other studies did not support a mediatory role of air pollution in the associations between green spaces and foetal growth and blood pressure in chil- dren (Dadvand et  al. 2012b; Hystad et  al. 2014; Markevych et  al. 2014a, b). A study from Finland reported that adolescents living in more natural areas with higher biodiversity had richer skin microbiota, which in turn was associated with lower risk of atopy through improved immunoregulation (Hanski et  al. 2012). Similarly, higher surrounding greenness was related to fungi diversity and variation in house dust in Germany (Weikl et  al. 2016), which in turn was associated with lower risk of wheezing in children (Tischer et  al. 2016). Improved immunoregula- tion induced by an enriched environmental microbiome in green spaces has not only been suggested to reduce the risk of allergic conditions but has also been postulated to enhance brain development (Rook 2013). Few studies have proposed physical P. Dadvand et al.