Abstract：
Air pollution induced by fine particulate matter with diameter ≤ 2.5 μm (PM2.5) poses a significant challenge for global air quality management. Understanding how factors such as climate change, land use and land cover change (LULCC), and changing emissions interact to impact PM2.5 remains limited. To address this gap, we employed the Community Earth System Model and examined both the individual and combined effects of these factors on global surface PM2.5 in 2010 and projected scenarios for 2050 under different Shared Socioeconomic Pathways (SSPs). Our results reveal biomass-burning and anthropogenic emissions as the primary drivers of surface PM2.5 across all SSPs. Less polluted regions like the US and Europe are expected to experience substantial PM2.5 reduction in all future scenarios, reaching up to ~5 μg m-3 (70 %) in SSP1. However, heavily polluted regions like India and China may experience varied outcomes, with a potential decrease in SSP1 and increase under SSP3. Eastern China witness ~20 % rise in PM2.5 under SSP3, while northern India may experience ~70 % increase under same scenario. Depending on the region, climate change alone is expected to change PM2.5 up to ±5 μg m-3, while the influence of LULCC appears even weaker. The modest changes in PM2.5 attributable to LULCC and climate change are associated with aerosol chemistry and meteorological effects, including biogenic volatile organic compound emissions, SO2 oxidation, and NH4NO3 formation. Despite their comparatively minor role, LULCC and climate change can still significantly shape future air quality in specific regions, potentially counteracting the benefits of emission control initiatives. This study underscores the pivotal role of changes in anthropogenic emissions in shaping future PM2.5 across all SSP scenarios. Thus, addressing all contributing factors, with a primary focus on reducing anthropogenic emissions, is crucial for achieving sustainable reduction in surface PM2.5 levels and meeting sustainable pollution mitigation goals.
摘要：
直径≤2.5μm的细颗粒物(PM2.5)所造成的空气污染对全球空气质量管理提出了重大挑战。了解气候变化等因素，土地利用和土地覆被变化(LULCC)，不断变化的排放对PM2.5的影响仍然有限。为了解决这个差距，我们采用了社区地球系统模型，并研究了这些因素对2010年全球地表PM2.5的单独和综合影响，以及在不同的共享社会经济途径（SSP）下2050年的预测情景。我们的结果表明，生物质燃烧和人为排放是所有SSP中地表PM2.5的主要驱动因素。预计美国和欧洲等污染较低的地区在未来的所有情况下都将大幅减少PM2.5。在SSP1中达到~5μgm-3(70%)。然而,像印度和中国这样污染严重的地区可能会经历不同的结果，在SSP3下，SSP1可能降低，而SSP3下增加。在SSP3下，中国东部的PM2.5上升了约20%，而在同样的情况下，印度北部的PM2.5上升了约70%。根据地区的不同,预计仅气候变化就会使PM2.5变化至±5μgm-3，而LULCC的影响似乎更弱。由LUCC和气候变化引起的PM2.5的适度变化与气溶胶化学和气象效应有关，包括生物挥发性有机化合物的排放，SO2氧化,和NH4NO3的形成。尽管他们的角色相对较小，LUCC和气候变化仍然可以显着影响特定地区未来的空气质量。有可能抵消排放控制举措的好处。这项研究强调了人为排放变化在所有SSP情景中塑造未来PM2.5的关键作用。因此，解决所有促成因素，主要关注减少人为排放，对于实现表面PM2.5水平的可持续降低和实现可持续的污染缓解目标至关重要。
