Integrated assessment of impacts on NO2 and PM2.5 concentrations, population exposure, and CO2 emissions of biomethane deployment scenarios

Climate mitigation strategies increasingly prioritize interventions that deliver simultaneous benefits for greenhouse-gas reduction, air quality and public health. This study quantifies the co-benefits of scaling biomethane deployment in the Po Valley (Northern Italy), a European air pollution hotspot, comparing two policy-relevant supply levels (2.3 and 6 bcm). An integrated pathway is assessed where biomethane is used for electricity generation to support partial electrification of the vehicle fleet, while digestate, the solid and liquid residue of the anaerobic digestion process, is utilized in agriculture with improved manure management protocols. A bottom-up integrated assessment framework links energy, traffic and agricultural measures to emission changes, ambient concentrations of NO 2 and PM2.5, population exposure, and attributable mortality, and provides the analysis of uncertainty propagated across the modelling chain. Both deployment levels reduce CO 2 emissions and lower population exposure to NO 2 and PM2.5, yielding measurable public health benefits. Direct comparison of 2.3 and 6 bcm scenarios estimates the marginal co-benefits of scaling biomethane deployment and highlights how coordinated actions across the energy, transport, and agricultural sectors can enhance health-relevant decarbonization in highly polluted regions. Scalability indicators, namely ΔCO 2 , ΔNO 2 , and ΔPM2.5 per bcm of biomethane, and the incremental benefits of scaling from 2.3 to 6 bcm are estimated, providing a basis for comparing alternative decarbonization pathways in other settings.