Evolution of ozone-precursor sensitivity in the Guangdong-Hong Kong-Macao Greater Bay Area of China under the backdrop of climate change

China is facing the dual challenges of worsening ozone (O 3 ) pollution and climate change. Better understanding the cause of O 3 pollution and its response to climate change is crucial for developing an effective O 3 control strategy in the coming years. In this study, a localized three-dimensional numerical modeling system was applied to investigate the long-term evolution of ozone -precursor sensitivity (OPS) over the Guangdong -Hong KongMacao Greater Bay Area (GBA) during September 2030, 2040 and 2050 under different climate scenarios, including four Representative Concentration Pathway (RCP), the Nationally Determined Contribution (NDC), and carbon neutrality (NEU). RCP emissions were corrected both temporally and spatially by bounding with the actual emissions in 2020 to reduce the uncertainty of future emission estimation. The atmospheric oxidative capacity -based HO 2 /OH indicator was used to quantify the variations of OPS. The percentage of NO x -limited area over the GBA will increase by 9.8%, 14.8% and 16.9% under RCP2.6, RCP4.5 and RCP8.5 in 2050, comparing with those in 2020. NO x -limited area under NEU showed a greater increase by 23.1%, as a result of larger reduction degree of NO x than VOCs. This highlights that deep NO x emission reduction, mostly driven by the structural adjustments in industry, energy, and transportation under the "2060 carbon neutrality " strategy, will accelerate OPS transition into NO x -limited and ensure the gradual improvement of O 3 pollution. NO x emission control in some urban areas still in the VOCs-limited OPS in 2050 under NEU, e.g., Guangzhou and Hong Kong, need to be strengthened to speed up O 3 mitigation. The findings of this study would improve our understanding on the long-term trends of OPS in the GBA under the backdrop of climate change, and provide guidance for the synergistic reduction of greenhouse gases and air pollutants in the future.