Ambient air pollution has become one of the key issues in China because it is highly associated with economic development, energy consumption, the atmospheric environment, and public health. Ambient air quality standards are guidelines of environmental management and fundamentals of air pollution emission control. To adapt to the changing environmental situation, China’s ambient air quality standard GB 3095 was established in 1982, amended in 1996, again in 2000, and most recently in 2012. This article presents a historical analysis on the evolution of China’s ambient air quality standards focusing on the critical pollutants and their concentration thresholds, as well as a comparative analysis that illustrates the differences to important developed countries and international organizations. The results show that the ambient air quality standard in China features a progressive update in pollutant items, more stringent concentration thresholds, and more scientific planning. Although there are differences in the economic, technological, and environmental development levels, China’s latest ambient air quality standard GB 3095-2012 is found to be comparable with other important standards. However, the support of macro policies and technical measures are necessary to ensure the standard is implemented more effectively.

As a stationary intensification processing technology, cyclonic separation has been widely used for multiphase gas-particle separation in the fields of fluidized processing, energy utilization, material synthesis and aerosol classification. The mathematical characterization of gas-particle dynamics inside a cyclone separator is vital in implementing performance prediction, structural design, parameter optimization, and/or techno-economic assessment. In past decades, significant efforts have been made to develop modeling approaches to gas-particle separation processing and dynamics inside cyclone separators. However, these modeling approaches are derived from different fundamentals of theory and method. Hence, their applicability and effectiveness have not been comprehensively validated or verified, particularly for those cyclones with varied geometrical dimensions, operating conditions, and multiphase properties. In the current review paper, various types of modeling approaches from the 1940s to the present are summarized, compared, and evaluated for gas-particle cyclonic separation dynamics, focusing on the modeling of gas flow pattern, pressure drop, and gas-particle separation behaviors including the particle cut-size and grade efficiency. The modeling for dense medium cyclones was also involved. Finally, the future outlook is highlighted to advance the modeling of gas-particle separation dynamics in cyclone separators.