## 1 Introduction  
Climate change is an urgent global concern and one of the paramount challenges confronting the world today. The international community is actively engaged in efforts to tackle climate change [1]. This necessitates achieving carbon neutrality, which refers to attaining a balance between the net carbon dioxide (CO\({}_{2}\)) emissions and removal or offsetting measures. Fundamentally, two primary approaches can be adopted to accomplish this objective: reducing carbon emissions and enhancing carbon sinks [2, 3]. While technological advancements and policy interventions contribute significantly to emission reduction, harnessing the natural capacity of ecosystems to absorb and sequester carbon is equally indispensable [4]. The gross primary productivity (GPP) of terrestrial ecosystems is the largest component of the Earth's carbon cycle [5, 6], as it determines the initial material and energy that land ecosystems obtain from external sources [7]. GPP serves as the primary pathway for terrestrial carbon exchange between land and atmosphere, playing a crucial role in regulating the Earth's carbon balance [8]. Capturing atmospheric CO\({}_{2}\) through vegetation photosynthesis is a vital strategy for achieving carbon neutrality [9]. Therefore, accurate estimation of GPP is essential for assessing the potential of terrestrial ecosystems to sequester carbon. Rising atmospheric CO\({}_{2}\) concentrations impact GPP in both direct and indirect ways simultaneously. The direct way is mainly referred to as the CO\({}_{2}\) fertilization effect, suggesting that the increase in atmospheric CO\({}_{2}\) concentration stimulates the photosynthesis process [10; 11]. However, the enhancement trend of carbon sink is slowing down and is projected to be averted in the future [12; 13]. The indirect way represents the impact through modulating the environmental conditions, such as meteorological parameters and soil mineralization. For instance, variations in meteorological factors could result in a decrease in carbon sequestration potential. Future warming-induced extreme droughs may lead to losses in net primary productivity (NPP) [14]. Conversely, increased precipitation in wet regions could reduce temperatures and radiation, thereby suppressing vegetation growth. Additionally, an expanding atmospheric water vapor pressure deficit (VPD) might diminish vegetation productivity [15]. The combined impact of these factors makes the estimation of future carbon sink potential challenging. The Chinese government has proposed achieving national carbon neutrality by 2060. Effective measures to reduce carbon emissions have been implemented and are planned for future implementation. Research indicates that air pollutants and greenhouse gas emissions share common roots, sources, and processes. Therefore, there is widespread attention from governments and scholars towards a synergetic approach to air pollution control and carbon neutrality [16; 17]. Integrated scenarios for reducing anthropogenic air pollutant emissions have been proposed, such as the dynamic projection model for emissions in China (DPEC) dataset [18]. These carbon-neutral pollutant emission reduction (PER) measures impact the concentration of air pollutants [19], which further affect meteorological elements and influence vegetation growth through their radiative effects. However, the specific impact of this effect on vegetation carbon uptake remains unexplored. In case of the ambiguous GPP variation trends caused by global climate change and CO\({}_{2}\) concentration rising [12; 13; 14; 20], the feedback of PER measures on GPP becomes imperative for achieving the carbon neutrality goal, especially in rapidly developing and severely polluted regions such as China. This study aims to evaluate the impact of PER on GPP in China under the context of carbon neutrality.