Otu, Ekpo and Ashworth, Kirsti and Tsekleves, Emmanuel and Ackley, Aniebietabasi (2025) Assessing air pollution health impacts in Lancaster City centre : a hybrid modelling study of urban planning mitigation scenarios using the APEHI framework. Air Quality, Atmosphere & Health. ISSN 1873-9318
Full text not available from this repository.Abstract
Air pollution interventions often focus on reducing emissions but rarely account for dynamic population exposure or public health outcomes. This study evaluates the effects of traffic-reduction scenarios in Lancaster (UK) using a novel Air Pollution Exposure Health Index (APEHI) framework, which builds on previous exposure risk metrics to support non-health experts in assessing exposure-related health risks. Baseline conditions were compared with three intervention scenarios using seasonal traffic and pedestrian counts, air quality measurements, spatiotemporal activity maps and regression models. Scenario 1 implemented full vehicle restrictions (excluding buses and emergency services) year-round, reducing by 80% and doubling pedestrian flow. Scenario 2 applied the same restrictions during daytime hours (07:00–18:00), cutting overall vehicle traffic by 63% and increasing pedestrian flow by 78%. Scenario 3 restricted traffic during peak periods (07:00–11:00 and 15:00–19:00), producing a 57% reduction in daily vehicle flow and increase in pedestrian flow. Across scenarios, NO₂ and PM₁₀ concentrations declined by up to 25% and 16%, respectively. However, a counterintuitive outcome emerged where, overall exposure risks and PM₁₀-related health impacts rose by 20–27% despite these reductions, largely due to rising pedestrian density and persistent background emissions. Sensitivity testing revealed that even small changes in intervention assumptions, such as variations in pedestrian density or traffic flow, can significantly influence exposure-related health outcomes. For instance, a 10% increase in pedestrian flow or a shortfall in traffic mitigation could raise exposure-related health risks by an additional 5–12%. These results show emission-reduction alone may not deliver proportional health benefits and should be complemented by exposure-aware strategies that consider human mobility patterns and residual pollution sources. Therefore, integrating tools such as APEHI into planning processes can help identify when and where people are most at risk, enabling targeted interventions that maximise health gains while maintaining urban functionality. Graphical Abstract