Strengthening the implementation of national policy agenda in urban areas to face multiple environmental stressors: Italy as a case study.

Multiple environmental stressors threaten the environmental quality in urban areas.Several policies were implemented in Italy to improve environmental quality, following the rationale that the more populated municipalities need high intervention priority and funds. Nevertheless, this approach not necessarily ensures to address real environmental challenges. This study aims to provide an innovative approach to explore interventions' priority at the national scale, based on Environmental Quality Standards (EQS) of five factors related to three environmental stressors, air pollution (O 3 , PM 10 , NO 2), thermal stress (heatwave days), and hydraulic vulnerability (flooding events). A multi-criteria analysis assessed the cumulative effect of factors by combining them into a single Aggregate Index of Challenge (AIC), and a hotspot analysis identified AIC spatial aggregation through the territory. Finally, the spatial mismatch between Italian environmental policies and the co-occurrence of factors was explored. Results evidenced EQS exceedances in the national territory of O 3 for 89%, PM 10 for 8%, NO 2 for less than 1%, heatwaves for 45%, and hydraulic vulnerability for 10%. AIC highlighted that 43% of the national surface shows the coexistence of at least two factors in EQS exceedance. Results highlighted that administrative boundaries are not sufficient to delimit an area of analysis and intervention as opposed to an evidence-based approach which seems promising for enhancing the costeffectiveness of funds allocation as well as their return in terms of human wellbeing. This study provides a novel approach to enhance environmental policies and planning, giving insight for future research, especially for Nature-Based Solutions implementation, performance, and multifunctionality. • Multi-criteria analysis was performed to assess co-occurrence of stressors. • Intervention priority was identified based on aggregate indices of challenge. • 43% of the Italian territory is simultaneously threatened by multiple stressors. • High stressors heterogeneity is found within the analyzed administrative domains. • Evidence-based approach can improve cost-effectiveness of policies in urban areas. [ABSTRACT FROM AUTHOR]