Natural gas shortage jeopardized China’s clean air goals

A natural gas shortage caused a major redistribution of air pollution related to China’s clean air actions in the winter of 2017

November 24, 2020

New study from the MPI for Chemistry highlights the interdependence of energy policies, air quality control measures, and climate change mitigation.

A natural gas shortage caused a redistribution of air pollution from North to South China during the China’s clean air actions in the winter of 2017. The figure shows distinctly different patterns of ambient PM2.5 changes in northern and southern China during the heating period 2017. Left: The observed relative changes in PM2.5 concentrations during the heating period 2017 compared to 2016. Right: The emission-induced relative changes in PM2.5 concentrations over zoom-in areas (i.e., the “2+26” cities in the north marked with the blue boundary line and the four provinces in the south, Hubei, Hunan, Anhui and Jiangxi, marked with the red boundary line). Black solid lines represent the North–South Central Heating Supply Line.

© doi: 10.1073/pnas.2007513117

A natural gas shortage caused a redistribution of air pollution from North to South China during the China’s clean air actions in the winter of 2017. The figure shows distinctly different patterns of ambient PM2.5 changes in northern and southern China during the heating period 2017. Left: The observed relative changes in PM2.5 concentrations during the heating period 2017 compared to 2016. Right: The emission-induced relative changes in PM2.5 concentrations over zoom-in areas (i.e., the “2+26” cities in the north marked with the blue boundary line and the four provinces in the south, Hubei, Hunan, Anhui and Jiangxi, marked with the red boundary line). Black solid lines represent the North–South Central Heating Supply Line.

© doi: 10.1073/pnas.2007513117

Air pollution and climate change mitigation are key issues of human-environment interaction in the Anthropocene. The effectiveness and impact of environmental remediation measures are closely linked to energy structures and industrial activities. A recent study from researchers at the Max PIanck Institute for Chemistry (MPIC) shows that a natural gas shortage during winter 2017 has jeopardized the objectives and benefits of the Chinese “coal-to-gas” policy and led to a deterioration of air quality for large areas and populations in southern China.

To solve the air pollution problem in the North China Plain (NCP), “coal-to-gas” and “coal-to-electricity” strategies have been implemented to promote the use of clean and low carbon fuels in northern China. A large-scale implementation of emission mitigation measures in the winter of 2017 led to a dramatic reduction of fine particulate matter (PM2.5) concentrations of ~14% compared to 2016. In contrast to the air quality improvement in northern China, however, large areas in southern China showed an unexpected upsurge of PM2.5 concentrations by ~15%.

Urban haze in Beijing.

© Guolin Han

Urban haze in Beijing.

© Guolin Han

Combining satellite and ground-based measurements, emission estimates, and chemical transport model simulations, the MPIC researchers found that the increase of air pollution in southern China was due to a severe shortage of natural gas during that winter. “This shortage led to the use of less clean energy sources, stronger pollutant emissions, and a deterioration of air quality in the regions affected by the gas-shortage”, says Siwen Wang, a postdoctoral researcher at the MPIC.
“The regional redistribution of air pollution, triggered by the “coal-to-gas” action in northern China in the context of natural gas shortage, may jeopardize the overall air quality benefits to be expected from the transition toward cleaner energy”, says Hang Su, group leader in the MPIC Multiphase Chemistry Department.

“Our findings demonstrate the importance of regional, national, and international energy supplies for achieving the co-benefits of air pollution and climate change mitigation. They highlight the need for efficient coordination between environmental and energy policies to address the grand challenge of an actionable future”, summarizes Yafang Cheng, leader of an independent Minerva Research Group at the MPIC.