Page - 125 - in Biodiversity and Health in the Face of Climate Change

125 brain structure to assess whether lifelong exposure to green space surrounding the residential address was associated with beneficial structural changes in the develop- ing brain in 253 urban schoolchildren (Dadvand et  al. 2018a). This study detected that such exposure was associated with an increase in grey matter volume in the prefrontal and premotor cortices and an increase in white matter volume in the pre- frontal, premotor and cerebellar regions. These structural changes were in turn asso- ciated with improved working memory and reduced inattentiveness. These findings provide novel evidence that long-term contact with green spaces is associated with beneficial and potentially lasting changes in brain structure. 6.5 Respiratory and  Allergic Conditions The available evidence on the effects of green spaces on asthma and allergic condi- tions in children is inconsistent (Lambert et  al. 2017). While a number of studies have reported a higher risk of allergic conditions and exacerbation of asthma in children in relation to green spaces (Dadvand et  al. 2014a; DellaValle et  al. 2012; Fuertes et  al. 2016; Lovasi et  al. 2013), others have shown no or even protective associations (Dadvand et  al. 2014a; Fuertes et  al. 2016; Hanski et  al. 2012; Lovasi et  al. 2008; Müller-Rompa et  al. 2018; Pilat et  al. 2012; Tischer et  al. 2017, 2018). These inconsistencies reflect the potential conflicting functions of green spaces in relation to these health outcomes. For example, green spaces can increase the risk of asthma and allergic conditions through releasing allergic pollens (DellaValle et  al. 2012; Lovasi et  al. 2013) and fungal spores (Bartra et  al. 2009; De Linares et  al. 2010), or through pesticides or fertilisers used for green space maintenance (Corsini et  al. 2012; see also Damialis et  al. Chap. 3, this volume). On the other hand, green spaces can prevent these conditions through enriching environmental biodiversity, mitigating exposure to air pollution and, to a lesser extent, encouraging physical activity and reducing the risk of obesity (Hanski et  al. 2012; Lovasi et  al. 2008; Pilat et  al. 2012). The heterogeneity in the available literature could also have been, in part, due to the poor metrics that did not take into account the differential allergenicity of different vegetation species or seasonal variation in their allergenic properties. Different types of green spaces (e.g. parks vs. forests) and different cli- mates/settings could also be contributing factors to such a heterogeneity. For exam- ple, a study from Spain reported that residing close to urban parks was associated with a higher risk of concurrent asthma and allergic rhinoconjunctivitis, while resid- ing close to natural green spaces (e.g. forests) was not (Dadvand et  al. 2014a). Another study that evaluated the impacts of green spaces on respiratory outcomes reported different impacts across two bio-geographic regions in Spain (Tischer et  al. 2017). In the Euro-Siberian region, characterised by a humid climate with water availability throughout the year, cold winters and maximum vegetation during sum- mer months (Alcaraz-Segura et  al. 2009), green spaces were negatively associated with wheezing. In the Mediterranean region, characterised by an arid climate with hot and dry summers, mild and rainy winters, and maximum vegetation between 6 Green Spaces and  Child Health and  Development