Stamp out household fuels to help fix China's air pollution woes
Restrictions on major sources of pollution may need revision following research that points to a giant, overlooked contributor. Phil Ritchie reports.
China’s plan to curb deadly air pollution by reducing emissions from transport and power plants may have a limited effect if households keep burning dirty fuels, new research suggests.
Published in Proceedings of the National Academy of Sciences and led by Peking University’s Jun Liu, the study explored regional contributions to pollution from the cities of Beijing, Tianjin and Hebei.
They found particulate matter – particles such as smoke, soot and dust floating in air – could be cut by almost half if houses were considered in regional emission plans.
“These benefits would be largest in the winter heating season when severe air pollution occurs,” Liu says.
“Household emissions, mostly from space heating and cooking with solid fuels, are an important and generally unrecognised source of ambient air pollution in China and other developing countries.”
In 2013 the Global Burden of Disease study found 800,000 premature deaths in China were linked directly to exposure to household pollution. It’s the second largest health risk in the country, ranked between high blood pressure and smoking.
In March this year, China released its latest five-year plan to reduce emissions. But does it matter if reductions are implemented on a city-by-city basis, or should they be applied to entire regions?
To gauge household particulate effects, Liu and colleagues simulated scenarios using data from Multiresolution Emission Inventory of China for January and February 2010. These data were fed into the Weather Research and Forecasting model coupled with Chemistry – a meteorology simulation that traces emissions, gases and aerosols.
Removing residential emissions in Beijing alone reduced particulate levels in the city by a daily average of 22%.
But if its neighbours Tianjin and Hebei also cut their household emissions, that number doubled, with potential reductions hovering around 40%.
Tianjin and Hebei benefitted enormously too, with 43% and 38% reductions respectively.
To put these figures in perspective, annual reductions of transport, power and industry sectors on particulate matter are 5%, 6% and 58% respectively.
The team admits the models didn’t consider local circumstances but says the study was intended to be used as a platform to further discussion about emission-reduction plans.
This work, Liu says, shows emission reduction must be across large regions and not focused on individual cities.