How China’s Clean Air Actions Have Tackled CO2 Emissions & Air Quality Issues

21-09-2022 | By Liam Critchley

China has undergone massive economic and industrial growth in the last few decades. With industrial growth on the scale China has experienced, the energy consumption level becomes much greater, as do the emissions of carbon dioxide (CO2) and other greenhouse gases. During this period of growth, China has become the largest energy consumer in the world, and the consumption of such large amounts of fossil fuels has resulted in large CO2 emissions and more severe air pollution.

Many cities in China suffer from air pollution issues, with many cities regularly being above what is deemed normal levels of PM 2.5 particles (fine particulate matter under 2.5 microns in size) in the air and having air quality indexes (AQI) that are deemed to be unhealthy for the residents. While a number of factors contribute to the air quality in and around cities, the emission of CO2 from industrial and agricultural processes plays a significant factor.

In 2013, to improve the air quality around China, the Chinese government enacted the Air Pollution Prevention and Control Action Plan (the Action Plan) to reduce the levels of PM 2.5 concentrations in key regions by the end of 2017. In 2018, this initiative was followed up with the second phase of the action plan, known as the Three-Year Action Plan for Winning the Blue Sky Defense Battle. The second phase required nationwide air quality improvements. 

Some of the energy-related measures implemented in China during these initiatives include energy use caps, energy structure adjustments, and energy efficiency improvements to tackle fossil consumption and CO2 emission reduction. Now that it’s been a couple of years since the initiative finished, a study has taken place which analyses all the data from the period of 2013-2020 and uses a modelling framework to assess the impact that the clean air measures have had on improving the air quality in China.

The CO2 emissions and PM 2.5 concentrations prior to 2013 had undergone explosive growth, but after the implementation of these initiatives, there was a plateau for four years after 2013. After eight years of efforts, the air quality has dramatically improved in China and has been primarily driven by the decline in air pollutant emissions. Below, we look in some more detail from the study about some of the specific areas where there have been improvements in both air quality and CO2 emissions.

Changes in Air Quality During After these Actions

Several air pollutants were measured and analysed to determine the difference in air quality. While PM 2.5 is important, the analysis also gave a more rounded approach and looked at sulphur dioxide (SO2) and nitrogen oxide (NOx) gases as well. During the period between 2013 and 2020, when the measures were implemented, sulphur dioxide emissions dropped by 69%, nitrogen oxide emissions fell by 28% and PM 2.5. concentrations dropped by 44%. This meant that the average annual concentration of PM 2.5 across 74 Chinese cities decreased from 72 μg m-3 in 2013 to 34 μg m-3 in 2020. While environmental factors play a role in PM 2.5 concentrations, reducing these air pollutant emissions has been characterised as one of the primary drivers of the improvement in air quality over this period.

Reduction of Carbon Dioxide Emissions and its Benefits

There were five main clear air methods that were implemented which led to a reduction in CO2 emissions. These were upgrades on industrial boilers, phasing out small and polluting factories, phasing out outdated industrial capacity, promoting clean fuels in the residential sector, and retiring yellow-label and old vehicles. Overall, the analysis showed that the implementation of the Clean Air Action avoided 0.57 Gt of human-caused CO2 emissions, which was 5.5% of the real-world emissions in 2020.

Between 2013 and 2022, outdated combustion facilities were replaced with larger, cleaner, and more efficient systems. This change improved the combustion efficiency of these facilities and reduced energy use—especially the use of coal. The five main methods of tackling CO2 emissions also led to a net energy saving of 0.25 Giga tons coal equivalent (Gtce) in 2020 and saved 1.06 Gtce of energy between 2013 and 2020.

The two most effective methods of reducing CO2 emissions were found to be phasing out old industrial facilities and upgrading industrial boilers. The phasing out of old facilities was estimated to reduce CO2 emission by 0.2 Gt, whereas industrial boilers was by 0.17 Gt. During the initiative to install newer combustion technologies, it’s estimated that 424 GW of small coal-fired boilers were eliminated and replaced by more energy-efficient boilers—and those which weren’t directly replaced were changed to use low-carbon energy sources, such as natural gas and biomass fuels.

In other areas, the promotion of clean fuel in the residential sector helped to reduce CO2 emissions by 0.12 Gt in 2020, with over 29 million households switching from coal-fired systems to either natural gas or electricity. This led to more than 7.5 GW of residential coal boilers being eliminated. On the industry side, the phasing out of small and polluting factories reduced emissions by 0.07 Gt, with around 660,000 polluting factories being shut down or upgraded. The retirement of more than 26 million yellow-label and old vehicles also provided a 0.06 Gt reduction in CO2 emissions.

Overall, it’s estimated that the clean air measures provided a cumulative CO2 emission reduction of around 2.66 Gt between 2013 and 2020. Some end-of-pipe pollution control devices that were installed increased emissions slightly, so the net cumulative emission reduction is thought to be around 2.43 Gt—which is 3.1% of China’s CO2 emissions between 2013 and 2020. The emission reduction was not evenly spread out, however, as there was a plateau between 2013 and 2017 due to the infrastructure adjustments, but from 2017 onwards, the energy savings and emission reductions rose sharply. The later years’ acceleration also meant that the Action Plan met its intended emission reduction and air quality improvement goals.

Looking Towards Other Countries

It’s no secret that a lot of other countries, especially major cities, suffer from air quality issues—especially in Central, East and South East Asia, where many of the larger cities experience smog-filled atmospheres at many points throughout the year. China has made great strides in reducing CO2 emissions, air pollutants and providing better air quality. It has also undertaken initiatives that are helping to phase out outdated technologies (energy efficiency-wise) and reduce the reliance on coal in the energy sector.

It’s thought that similar initiatives to those utilised in China could be realised in many other countries throughout Asia and across Africa to help improve air quality and reduce carbon emissions. Many countries in Asia and Africa rely heavily on fossil fuels and still emit a large amount of air pollutants and greenhouse gases (which is why many cities still get covered in smog), but this is having a negative impact on many people’s health around the world. 

Many governments are starting to prioritise the health of the citizens, and improving the air quality in and around major cities is one approach that governments can take to improve the health of the general public. Some of the measures implemented could offer ways of reducing the air problems in many countries and improve the overall air quality, but it’s also possible that the transformation towards low-carbon growth may not be realistic based on the financial state of each country—as large budgets are required to implement all the initiatives that China has done. Nevertheless, there is the potential for other countries to follow suit in some capacity if public health is a top priority from a governmental policy perspective.


Zhang Q. et al, Co-benefits of CO2 emission reduction from China’s clean air actions between 2013-2020, Nature Communications¸13, (2020), 5061

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By Liam Critchley

Liam Critchley is a science writer who specialises in how chemistry, materials science and nanotechnology interplay with advanced electronic systems. Liam works with media sites, companies, and trade associations around the world and has produced over 900 articles to date, covering a wide range of content types and scientific areas. Beyond his writing, Liam's subject matter knowledge and expertise in the nanotechnology space has meant that he has sat on a number of different advisory boards over the years – with current appointments being on the Matter Inc. and Nanotechnology World Association advisory boards. Liam was also a longstanding member of the advisory board for the National Graphene Association before it folded during the pandemic.