Global air pollution levels have increased in recent years, posing major health challenges. Although there is already evidence that residents of large cities and vulnerable groups such as the elderly and children are at higher risk of exposure to air pollution, there is a need to expand new perceptions in the face of a new phase of urbanization and demographic change in the future. In the face of population decline and the phenomena of aging and childlessness, it has become a pressing issue how Japan should respond to future national health risks associated with air pollution. However, no studies have yet comprehensively considered the long-term effects of emission reduction measures and future demographic changes on population exposure risks. Therefore, we developed methods to assess future population exposure risks under different combinations of emission reduction measures and demographic change scenarios. The results show that: electrification measures may not effectively reduce pollutants compared to end-of-pipe technologies and renewable energy. However, they offer long-term benefits in lowering ozone concentration and exposure risks. Over the next 30 years, urban populations under 15 years old show a negative correlation with PM and an inverted U-shaped correlation with ozone. The elderly population's correlation with PM weakens over time, with no clear correlation with ozone. The correlation between population size and PM concentration varies for different classes of cities: positive for small cities, negative for medium cities, and negligible for large cities. No correlation was observed between ozone concentrations and urban population. Under equivalent abatement scenarios, the differences in exposure between the SSP scenarios are not large, but the SSP3 and SSP4 scenarios will bear a heavier healthcare burden and exposure inequity.

中文翻译：

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2030 年和 2050 年日本不同年龄组和城市之间 PM2.5 和臭氧暴露的不平等

近年来，全球空气污染水平有所增加，带来了重大的健康挑战。尽管已有证据表明大城市居民和老年人、儿童等弱势群体暴露于空气污染的风险较高，但面对新阶段的城市化和人口结构变化，有必要拓展新的认知。未来。面对人口减少和老龄化、少子化现象，日本如何应对未来与空气污染相关的国民健康风险已成为紧迫问题。然而，目前还没有研究全面考虑减排措施和未来人口变化对人口暴露风险的长期影响。因此，我们开发了评估不同减排措施和人口变化情景组合下未来人口暴露风险的方法。结果表明：与末端技术和可再生能源相比，电气化措施可能无法有效减少污染物。然而，它们在降低臭氧浓度和暴露风险方面提供了长期好处。未来30年，15岁以下城市人口与PM呈负相关，与臭氧呈倒U型相关。随着时间的推移，老年人口与PM2.5的相关性逐渐减弱，而与臭氧的相关性则不明显。不同类别城市的人口规模与PM2.5浓度之间的相关性有所不同：小城市为正相关，中等城市为负相关，大城市可忽略不计。没有观察到臭氧浓度与城市人口之间存在相关性。在同等减排情景下，SSP情景之间的暴露差异并不大，但SSP3和SSP4情景将承受更重的医疗负担和暴露不公平。