Quantitative assessment of vegetation-driven removal of key air pollutants and potential health benefits in the air pollution transport corridor region of China

Vegetation can intercept and adsorb both particulate matter and gaseous pollutants, potentially mitigating associated health risks. As a pilot zone for transboundary transport and coordinated control of atmospheric pollutants in the Beijing-Tianjin-Hebei region, a comprehensive, quantitative understanding of how vegetation-driven reductions in PM_2.5, NO₂, and O₃ translate into decreased health and economic burdens in the "2 + 26" urban agglomeration is still lacking. In this study, we integrated multi-source remote-sensing and experimental data and used a dry deposition modeling framework based on i-Tree Eco, an excess mortality model, and the value-of-statistical-life framework to quantify and analyze the 1) extent to which vegetation removed three representative atmospheric pollutants, 2) impact of this removal on air quality, and 3) subsequent reduction in excess mortality and economic losses. First, vegetation cover and pollutant concentrations were found to be spatially heterogeneous. In the piedmont zone, a distinct "low vegetation-high PM_2.5/NO₂ pollution" pattern was observed. Second, between 2013 and 2020, vegetation cumulatively removed 3.54 × 10⁶ tons of O₃, substantially more than those of PM_2.5 (1.07 × 10⁶ tons) and NO₂ (4.73 × 10⁵ tons). The improvement rate for PM_2.5 (0.15 %) was approximately one order of magnitude higher than those for NO₂ and O₃. Third, in 2022, model-based estimates suggest that vegetation dry deposition averted approximately 27.6 excess deaths and prevented an estimated US$19.06 million in economic losses. These findings provide robust scientific evidence of the critical role vegetation plays in regional air pollution mitigation and public health protection.