Core Viewpoint - The Ministry of Ecology and Environment has released a draft for public consultation on the revised "Ambient Air Quality Standards," which aims to tighten concentration limits for particulate matter and gases like sulfur dioxide (SO2) and nitrogen dioxide (NO2) [1][7]. Group 1: Reasons for Revising Air Quality Standards - The current standards have led to significant improvements in air quality, with PM2.5 annual average concentration decreasing by 36% from 2015 to 2024, and the number of heavily polluted days reduced by 68% [2][8]. - The revision aims to further protect public health, as PM2.5 remains the most harmful air pollutant according to the World Health Organization (WHO) [2][8]. - The revision supports the "Beautiful China" initiative, which targets an average PM2.5 concentration of below 25 micrograms per cubic meter by 2035, addressing the gap where nearly half of the compliant cities still exceed this limit [2][8][9]. Group 2: Key Changes in the Standards - The revised standards will tighten the PM2.5 annual average and daily average secondary limits to 25 micrograms per cubic meter and 50 micrograms per cubic meter, respectively [4][10]. - PM10 annual and daily average secondary limits will also be tightened to 50 micrograms per cubic meter and 100 micrograms per cubic meter [4][10]. - The revision includes stricter limits for sulfur dioxide and nitrogen dioxide, while ozone and carbon monoxide limits will remain unchanged [11]. Group 3: Implementation of the Revised Standards - The revised standards will be implemented in two phases: the first phase (2026-2030) will introduce transitional limits of 30 micrograms per cubic meter for PM2.5 annual average and 60 micrograms per cubic meter for daily average [5][12]. - The second phase, starting in 2031, will fully enforce the revised limits for particulate matter and gases [5][12]. - The transitional limits are designed to allow for a smooth implementation and to reduce short-term pressures on economic and social development [6][12].