MEIC team reveals the drivers of China’s air quality improvement in recent years

2019-11-18 | MEIC team

On November 18, 2019, MEIC team online published a paper entitled “Drivers of improved PM2.5 air quality in China from 2013 to 2017” in the Proceedings of the National Academy of Sciences (PNAS), which assessed the improvement and health benefits of national atmospheric fine particulate matter (PM2.5) pollution from 2013 to 2017, and quantitatively analyzed the air quality improvement contributions of various policies in the “Air Pollution Prevention and Control Action Plan” (hereinafter referred to as “the Action Plan”).

With the rapid development of economy, air pollution incidents occur frequently, endangering the public health of residents and causing widespread concerns in society. In order to solve the serious air pollution problem and effectively improve the air quality, the State Council issued and implemented “the Action Plan” on September 2013, which describes the general thoughts on air pollution prevention and control during the present and future period, put forwards 10 measures and 35 key tasks, and specifies the air quality improvement requirements for the whole country, key regions, and key cities. Since the implementation of “the Action Plan”, the air pollution in key regions has improved significantly. During this process, how much the various policies contribute to the air quality improvement has always been a concern issue to the government and the public.

In order to comprehensively evaluate the effectiveness of the implementation of “the Action Plan”, the Chinese Academy of Engineering organized the final evaluation of implementation effects of “the Action Plan”, analyzed the air quality improvement from 2013 to 2017, sorted out the implementation and effect of various policies, and evaluated the contributions of various policies to ambient air quality improvement, as well as analyzed the existing problems and put forward suggestions to promote the scientific and effective development of the next step. Among the evaluation work, the MEIC team first summarized the air pollution control measures during the five-year period. On the basis of multi-resolution emission inventory model (MEIC) developed by Tsinghua University, combining with the atmospheric chemical transport model and the epidemiological exposure-response functions, we evaluated the main drivers of air quality improvement of during 2013-2017, and identified the measure-specific contributions in the “the Action Plan”. We found that, since the implementation of “the Action Plan”, The estimated national population–weighted annual mean PM2.5 concentrations decreased from 61.8 to 42.0μg/m3, which represents a 32% reduction.
Emission reduction has been the leading driver in the air quality improvement in recent years, and the interannual changes in meteorological conditions have little impact. Nationally, we estimated that emission reductions and meteorological conditions could explain 91% and 9% of the total decrease in PM2.5 concentrations from 2013 to 2017, respectively.
Through the implementation of the main measures in “the Action Plan”, national SO2, NOx, and primary PM2.5 emissions are reduced by 16.4 Mt, 8 Mt, and 3.5 Mt, respectively. strengthened industrial emission standards (power plants and emission-intensive industrial sector), upgrades on industrial boilers, phasing out outdated industrial capacities, and promoting clean fuels in the residential sector were major effective measures in reducing PM2.5 pollution and health burdens. These measures were estimated to contribute to 6.6, 4.4, 2.8, and 2.2 μg/m3 declines in the national PM2.5 concentration in 2017, respectively.

Measure-specific contributions to emission reductions, PM2.5 abatements, and avoided excess deaths

Our study quantified the contribution of different pollution control policies to the rapid improvement in PM2.5 air quality across China from 2013 to 2017, thereby highlighting the effectiveness of the Action Plan, and the measure-by-measure evaluation provides insights into future clean air policymaking in China and in other developing and polluting countries. Despite the remarkable air quality improvements introduced by the Action Plan, air pollution in China remains severe. For example, 64% of 338 prefecture-level cities in China failed to meet the national standard for annual PM2.5level in 2017. Therefore, continuous and effective emission control measures are still of high priority. Future clean air actions should be designed based on the experiences of the Action Plan implemented from 2013 to 2017 and should overcome its deficiencies. The national ozone pollution has accelerated, and the coordinated controls of PM2.5 and ozone pollution has become an urgent problem to be solved.

The study further suggested that in order to win the battle to defend the blue sky, it is necessary to strengthen and deepen the effective measures and policies of the Action Plan, and make efforts to release the pollution reduction potential of energy, industrial, and transportation structural adjustment; meanwhile, strict control policies for other industries, implement diesel engine pollution prevention and control action plans as well as VOCs emission control projects, promote NH3 emission controls in agriculture sector, strength the controls on NOx, VOCs, and NH3 to achieve continuous air quality improvement and win the blue sky battle.

Academician Jiming Hao and Academician Kebin He from School of Environment, and Professor Qiang Zhang from Department of Earth System Science in Tsinghua University are the co-corresponding authors of this paper. Qiang Zhang, Yixuan Zheng, and Dan Tong are the co-first authors of this paper. More than 20 academicians and experts from Peking University, Chinese Academy of Meteorological Sciences, Environmental Planning Institute of Ministry of Ecology and Environment, Research Center for Ecological Environment of Chinese Academy of Sciences, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, National Climate Center, Institute of Atmospheric Physics, Chinese Academy of Sciences participated in this research. The research was supported by the Chinese Academy of Engineering, the National Natural Science Foundation of China, and the National Key Research and Development Program.