Ambient air quality baseline and standard formulation methods and their enlightenment for China

China has accomplished remarkable achievements in air pollution control over the past decade, demonstrated a significant improvement in its ambient air quality, and gained immense and in-depth experience in air pollution control. At this stage, researchers should initiate research on formulating an ambient air quality baseline for better sustainable development. This paper details three internationally popular methods for ambient air quality baseline and standard formulation. These methods are mainly based on the aspects of human health, vegetation exposure, and chemical indices of the soil/water ecological system. A series of evaluation indices commonly used worldwide have been comprehensively summarized, and their advantages and disadvantages have also been compared. On this basis, the present paper summarizes China’s ambient air quality baseline and standard research based on human health, vegetation exposure, and chemical indices of the soil/water ecological system. Subsequently, this paper assesses the possibility of implementing the formulation method in China based on the above three aspects. For clarity, an analysis of the possible principled path was performed for establishing the environmental air quality baseline, including the probable structure of the initial period and the later advanced period of the formulation work. It should be noted that during the initial stage of work for the baseline formulation, the work can be appropriately simplified due to a lack of reference data and the unevolved nature of the working standard. However, after the foundation of the work is gradually enriched, the working principles should be gradually refined. Moreover, this paper briefly compares the role of the ambient air quality baseline with respect to the progress of ambient air standard formulation as well as its modification at the international and domestic levels. Furthermore, it illuminates the urgency and necessity for a well-fitted baseline for China based on the existing domestic study results regarding the ambient air pollution situation and pollution assessment system. Generally, to achieve the goal of building a healthy environment in China, it is crucial for the ambient air quality baseline, which is the foundation of the environmental air quality assessment system, to consider the unique safety red line of both the local human health and the ecology system during its scientific construction. Moreover, it is worth noticing that probable management difficulties may be accrued through a transformation from the ambient air quality baseline to the national standards, which should be adjusted according to the administrative characteristics of China to ensure steady progress and victory in the battle against ambient air pollution.