Schools with more vegetation have less traffic-related air pollution

- Reduced indoor and outdoor air pollution is associated with greenness within and around schools.

- Reduction in indoor air pollution was mediated by reduction in outdoor levels.

Greenness, that can be defined as the presence of trees, plants and vegetation, has been reported to improve mental and physical health. This study, led by the Center for Research in Environmental Epidemiology (CREAL), an ISGlobal allied center, investigated the association between greenness within and surrounding school boundaries and monitored indoor and outdoor levels of traffic-related air pollutants including NO₂, ultrafine particles, black carbon, and traffic-related PM_2.5 at 36 schools across Barcelona, in 2012. Levels of traffic-related air pollutants at schools were measured twice during two one-week campaigns separated by 6 months. Greenness was abstracted using satellite-derived data (5m × 5m resolution) and was measured within and 50 m of surrounding school boundaries.

Higher greenness within and surrounding school boundaries was consistently associated with lower indoor and outdoor air pollutant levels. Reduction in indoor air pollutant levels was partly mediated by the reduction in outdoor air pollutant levels.

“We observed some suggestions for larger reduction of air pollutant levels in schools with higher number of trees around them”, explains Payam Dadvand, leading author of this paper published in Science of the Total Environment.

“Considering the high burden of health effects of air pollutant exposure on schoolchildren, our findings might inform policymakers and health professionals about the importance of school greenness to avoid such burdens and at the same time to achieve other health co-benefits of greenness such as better behavioral development and school performance”, concludes Dadvand.

Reference:

Dadvand P, Rivas I, Basagaña X, Alvarez-Pedrerol M, Su J, De Castro Pascual M, Amato F, Jerret M, Querol X, Sunyer J, Nieuwenhuijsen MJ. The association between greenness and traffic-related air pollution at schools. Sci Total Environ. 2015 Apr 6.

Author of the picture: Anders Leipzing (Creative Commons / Wikipedia).