Forestation favours carbon neutrality and ozone air pollution abatement

Forestation-induced greening is known to increase carbon sinks and contribute to carbon neutrality. However, its impact on ozone air quality remains unclear due to the complexity of atmospheric chemistry and biosphere interactions. Using chemical transport models and meta-analysis, we quantified the effects of forestation on ozone air quality. In South China, where greening is most prominent, the 2005-2019 greening effects on ozone dry deposition and vertical transport significantly outweighed biogenic volatile organic compounds emissions, reducing mean surface maximum daily 8-hour average (MDA8) ozone by 1.4 ppbv during the growing season. Additionally, greening reduced vegetation damage by 15%-41% (depending on exposure metrics) in South China forests and increased forest carbon storage by 1.8 (1.6-2.1) Pg C. Future forestation opportunities could potentially double global forest land cover and leaf area, constrained by food security and biodiversity safeguards, and decrease global surface ozone air pollution by 20%-40% through direct biogeochemical pathways. Temperature feedbacks between the biosphere and atmosphere could amplify these ozone benefits by 8%-20%. Our findings indicate that forestation can benefit both carbon neutrality and ozone pollution control, highlighting the pivotal role of interactions between the biosphere and air pollution.