China's stricter clean heating policies may have saved thousands of lives

From 2015 to 2021, the impact of winter heating on China's capital and 27 other cities saw concentrations of fine particulate matter (PM_2.5) from heating activities reduce by 41.3% -- compared with a drop of 12.9% in other northern Chinese cities which use lower levels of clean fuels than the '2+26' cities.

China's centralised winter heating strategy is one of the world's largest energy-consumption systems -- providing free or heavily subsidised heating to urban residents. The system is usually switched on from mid-November to March.

Whilst coal has been the main heating energy source in northern China -- accounting for 83% of the total heating area in 2016 -- new policies have encouraged the use of cleaner fuels such as gas and electricity, reducing the dependence of urban areas on coal and rural areas on biomass.

Researchers from the University of Birmingham and Nankai University, China, published their findings in Environmental Science & Technology today, noting clear air quality benefits from the stricter clean heating policies in the '2 + 26' cities -- Beijing and Tianjin, plus 26 cities across Hebei, Shanxi, Shandong and Henan provinces.

Corresponding Professor Zongbo Shi, from the University of Birmingham, commented: "Using a novel approach combining machine learning with causal inference, we showed that heating in northern China was a major source of air pollution, increasing annual PM_2.5 concentrations by 8.9 µg m^-3 in 2015. However, clean heating policies have caused the annual PM_2.5 in mainland China to reduce significantly between 2015 and 2021, with significant public health benefits.

"Our research demonstrates the effectiveness of China's clean winter heating policies on reducing PM_2.5 -- with particular success for the stricter clean heating policies in '2 + 26' cities, which also led to a reduced impact of heating emissions on sulphur dioxide (SO₂). These results demonstrate clear air quality benefits from the stricter clean heating policies in '2 + 26' cities."

In addition to central heating, biomass burning was often used for heating in rural areas -- coal and biomass burning were often associated with severe haze episodes during the heating periods in northern China.

In 2013, China introduced the Air Pollution Prevention and Control Action Plan, which accelerated the use of centralised and district heating -- encouraging the switch to cleaner fuels.

In 2017, the Chinese central government issued its Clean Winter Heating Plan for Northern China, which aimed to increase the region's share of clean heating to 50% by 2019 and 70% by 2021 compared to the base scenario in 2016.

Additionally, the share of clean heating in '2 + 26' cities was to exceed 90% in urban areas, reaching 100% by 2021. In 2018, a three-year action plan to fight air pollution was issued. All these plans led to substantial air pollutant emission from the residential sector.

Co-author Professor Robert Elliott noted "Clean heating policies in northern China not only reduced air pollution but also greenhouse gas emissions, contributing to China's push for carbon neutrality. However, we found that heating remains an important source of air pollution in northern China, particularly in cities that are not part of the "2+26" cluster. Decarbonising heating should remain a key part of China's carbon neutrality strategy that not only reduces air pollution but also provide significant public health benefits."