Responses of fine particulate matter (PM2.5) air quality to future climate, land use, and emission changes: Insights from modeling across shared socioeconomic pathways

• Published in: The Science of the total environment Vol. 948; p. 174611
• Main Authors: Bhattarai, Hemraj, Tai, Amos P.K., Val Martin, Maria, Yung, David H.Y.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 20.10.2024
• Subjects: Air pollution; Anthropogenic emissions; Climate change; Earth system modeling; Fine particulate matter; Land use change; Earth system modeling; Climate change; Anthropogenic emissions; Air pollution; Fine particulate matter; Land use change
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2024.174611

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. [Display omitted] •Biomass-burning and anthropogenic emissions shape future PM2.5 trends in various SSPs.•Climate change and LULCC have modest impact on PM2.5, yet crucial for regional air quality.•PM2.5 is projected to reduce over 70 % in the US and Europe in sustainable pathway (SSP1).•PM2.5 worsens in SSP3 by 20 % in Eastern China and 70 % in northern India in 2050.•Crucial to target biomass-burning and anthropogenic emissions for sustainable PM2.5 reduction and achieving pollution goals