Environmental quality improvement with a green wall in an urban schoolyard: Hesiberdea case in Spain

Background

School environments are key areas for promoting children’s well-being and reducing health inequalities. In a period marked by urban environmental challenges and social inequalities, green interventions can serve as a tool to address these issues. Specifically, they can mitigate the negative impacts of environmental pollution in urban settings. The study analysed the impact on environmental quality of installing a green wall in an urban school playground.

Methods

Using a quasi- experimental design, concentrations of PM2.5, PM10 and NO₂ in the air, as well as noise levels, were compared inside and outside the schoolyard. Data were collected prior to the installation of the green wall, and 7 and 19 months later, using fixed continuous monitoring devices for one month at 10-minute intervals. Mixed models were used for the analysis of quantitative environmental data. Data collected before and after the intervention was paired for both intervention and comparison sites and models were adjusted by meteorological variables and day of the week.

Results

Seven months after the green wall was installed, statistically significant reductions in PM2.5, PM10 and noise levels have been observed (p-values < 0.001), although there was no difference in NO2 levels (p-value 0.602). Green wall effectiveness was enhanced in the next months. 19 months after, differences between intervention and comparison sites were more pronounced than in the first period of analysis for PM2.5, PM10 and noise levels. In total, reductions were of 65.6%, 59.6% and 3.9%, for PM2.5, PM10 and noise levels respectively, compared to the pre- and 19 months post-intervention periods.

Conclusions

The green wall intervention contributed to measurable improvements in schoolyard environmental quality. Nature-based solutions such as green walls may represent a feasible strategy for improving environmental conditions in urban schools, particularly in settings with limited space and high pollution levels.

Key messages

• The green wall significantly reduces levels of PM2.5, PM10 and noise in the schoolyard following its installation.

• The reduction in these levels increases as the months go by and the plants on the green wall grow.