What kind of weather is considered 'good weather'? Recently, the Ministry of Ecology and Environment and the State Administration for Market Regulation jointly issued two supporting technical specifications, the "Environmental Air Quality Standards" (hereinafter referred to as the "Standards") and the "Technical Regulations for Environmental Air Quality Index (AQI)" and "Technical Specifications for Environmental Air Quality Evaluation", which will be implemented from March 1st. The new standard has tightened the concentration limits for particulate matter and its main precursors, which means that "good weather" has a stricter "scale". What are the specific criteria for 'good weather'? The relevant person in charge of the State Administration for Market Regulation introduced that the new standard is led by tightening the concentration limit of PM2.5, and synchronously increases the concentration limit of other pollutants such as PM10, sulfur dioxide, nitrogen dioxide, etc. The standard requires that the first level limit of PM2.5 annual average concentration be adjusted to 10 micrograms per cubic meter, and the second level limit be adjusted to 25 micrograms per cubic meter; The first level limit of daily average concentration has been adjusted to 25 micrograms per cubic meter, and the second level limit has been adjusted to 50 micrograms per cubic meter. The second level limit for annual average concentration of PM10 has been adjusted from 70 micrograms/cubic meter to 50 micrograms/cubic meter, the second level limit for annual average concentration of sulfur dioxide has been adjusted from 60 micrograms/cubic meter to 20 micrograms/cubic meter, and the second level limit for annual average concentration of nitrogen dioxide has been adjusted from 40 micrograms/cubic meter to 30 micrograms/cubic meter. Standards are the cornerstone of environmental management, playing a strategic, fundamental, and leading role. ”Li Tianwei, Director of the Atmospheric Environment Department of the Ministry of Ecology and Environment, said that the 2012 version of the Environmental Air Quality Standards included PM2.5 for the first time, becoming a milestone in China's air pollution control. This revision is the second time since 2012 that the State Council Executive Meeting has deployed the revision of environmental air quality standards, and it is also the only one among more than 2400 environmental standards in the field of ecological environment that has been deployed and revised by the State Council Executive Meeting. The new standards are not implemented immediately in a one size fits all manner, but adopt a plan of "one revision, two-stage implementation". From March 1, 2026 to December 31, 2030, implement the concentration limits for the transitional phase; Starting from January 1, 2031, the revised concentration limits will be implemented nationwide. During the transition phase, the secondary limits for annual average and daily average concentrations of PM2.5 are 30 micrograms/cubic meter and 60 micrograms/cubic meter, respectively, while the secondary limits for annual average and daily average concentrations of PM10 are 60 micrograms/cubic meter and 120 micrograms/cubic meter, respectively. Why set a transition period? Li Tianwei summarized three considerations: first, not being greedy for too much and seeking perfection, grasping the key, and leading the reduction of other pollutants by tightening PM2.5; Secondly, we should not blindly follow the trend, strive for progress while maintaining stability, and benchmark against the Beautiful China 2035 target and the World Health Organization's second phase transition value, so that the standards are at an international intermediate level; Thirdly, we should not rush to achieve results, leave sufficient buffer, and allow time and space for fundamental measures such as structural adjustment and emission reduction at the source. The revision of standards reflects the goal and direction of improving air quality, rather than requiring immediate compliance. ”Li Tianwei said that the funding, technology, methods, and means required to meet the standards should be gradually followed up, and we should achieve the goal of 'jumping one step at a time'. Many people are concerned about the impact of stricter standards on air quality assessment results. The Ministry of Ecology and Environment has calculated using data from 2025 as an example: if the transitional stage limit is used for evaluation, the number of cities in China that meet PM2.5 standards will decrease from 271 to 205, and the proportion of excellent days will decrease from 88.1% to 83.6%; If the second stage limit evaluation is used, the number of eligible cities will further decrease to 140, and the proportion of excellent days will decrease to 78.3%. This does not mean that the air quality itself has declined, but rather that the evaluation standards have become stricter and the requirements for blue skies and white clouds have become higher. ”Li Tianwei emphasized, "We are now striving to shift from obvious improvement to better and more sustainable improvement." For cities with different foundations, differentiated policies will be implemented in different stages and categories. Cities with an annual average concentration of PM2.5 above 35 micrograms per cubic meter should continue to focus on structural and engineering emission reduction; Cities with concentrations ranging from 26 to 35 micrograms per cubic meter should make good use of the transition period to tap into their emission reduction potential; Cities with concentrations below 25 micrograms per cubic meter need to consolidate their achievements and steadily move towards excellence. Stricter standards, what the people are most concerned about is: Will the air they breathe be better? Li Tianwei introduced that the implementation of the new standards will promote the continuous decrease of PM2.5 concentration, effectively reduce the health risks of the population, and have a more prominent protective effect on the elderly, children, and susceptible groups. According to calculations, the ratio of governance investment to health benefits generated by this standard revision is close to 1:10. From the perspective of carbon reduction benefits, the new standards can effectively promote the cultivation and development of new quality productive forces such as clean energy and new energy vehicles, and drive the green and low-carbon transformation of industries, energy, and transportation structures. It is expected that from 2026 to 2035, various pollutant reduction measures can achieve a synergistic reduction of over 7 billion tons of carbon dioxide emissions. (New Society)