Mitigating ozone damage to ecosystem productivity through sectoral and regional emission controls: a case study in the Yangtze River Delta, China

The land ecosystems of China are estimated to provide an important sink for the increased atmospheric carbon dioxide (CO _2 ), but are undermined by severe ozone (O _3 ) pollution. Mitigation of O _3 damage to ecosystems remains a challenge considering that O _3 precursors are emitted from a wide range of anthropogenic sectors and O _3 formations are also affected by regional transport. Here, we combine chemical transport and dynamic vegetation models to quantify the benefits of sectoral and regional emission controls for the recovery of gross primary productivity (GPP) in the Yangtze River Delta (YRD). For sectoral emission controls, the largest mitigation of O _3 damage to GPP in YRD by 3.1 ± 0.4 and 2.2 ± 0.2 Gg[C] d ^−1 with 50% reductions in the emissions from industry and transportation sectors, respectively. For regional emission controls, reducing 50% anthropogenic emissions outside YRD can mitigate GPP losses by 18.6 ± 3.5 Gg[C] d ^−1 , larger than the recovery of 10.1 ± 1.6 Gg[C] d ^−1 by the 50% reductions of anthropogenic emissions within YRD. Moreover, summer months, especially July are the best period for GPP recovery from anthropogenic emission controls. Our results highlight the importance of sectoral and regional emission controls to mitigate O _3 damage to ecosystem productivities in YRD.