While ambitious greenhouse gas emissions reduction would lower levels of annual air-pollution deaths, an even larger number of deaths can be avoided through a strategical early retirement and replacement of super-polluting power plants, according to a new study. Researchers found that an additional six million lives would be saved between 2010 and 2050 by employing this approach.

Air pollution remains one of the largest environmental problems we are faced with and, in many cases, this pollution is related to fossil fuel and biomass power plants. In fact, electricity generation accounts for about one-seventh of humans’ exposure to harmful air pollutants such as fine particulate matter and about 40% of climate change-causing CO2 emissions in recent years.

We already know that we can address air pollution and climate change by eliminating fossil fuel plants (especially coal plants) as early as possible, but there’s more than one way of doing that. Qiang Zhang from Tsinghua University in China and a group of fellow researchers wanted to see how different approaches would reduce greenhouse emissions and air pollution-related deaths per individual power plant. They modelled the differences of several policy scenarios, using 2010 as a baseline (a year commonly picked in climate modelling) 

In 2010, the researchers estimate that there were 7.30 million premature deaths related to PM2.5 pollution. Of this global total, 12% were related to emissions from global fossil fuel- and biomass-fired power plants. Almost half of these deaths were related to coal-fired plants, mainly small and super-polluting units in low-income and emerging countries.

This trend continued over the years, with coal remaining as the foremost problem. From 2010 to 2018, 92% of deaths related to power plant emissions happened in developing countries, such as China, India and countries in Southeast Asia, the study showed. They are all countries whose energy sector deeply relies in coal energy, such as China, with over half of its energy supplied by coal. 

Using an ambitious model, according to which climate policies succeed in limiting global warming to 1.5ºC, the researchers found that shutting down the most polluting power plants could avoid 18% of future emissions and six million of the predicted deaths between 2010 and 2050 – compared to just implementing climate policies alone.

“Air pollution deaths are not an automatic and fixed co-benefit of all climate mitigation. Rather, pollution controls and strategic retirements of the most-polluting and harmful power plants may ultimately determine the extent to which health co-benefits are realized,” the researchers wrote in their paper published in Nature Climate Change.

Global disparities 

A map of PM2.5 exposure — not from this study.

The researchers then continued their models into the future to see what would happen. In many future scenarios, both the overall number of deaths and the share occurring in low-income and emerging economies would grow, with places like India, the Middle East and Africa, being the worst affected, according to the study’s findings. Deaths related to air pollution would quadruple in India between 2010 and 2050 under the baseline scenario, for example.

In 2050, 90% of deaths in the baseline scenario would occur in Asia due to rapid projected growth in fossil fuel-fired electricity demand and population. In addition, the Middle East and Africa make up more than half of PM2.5-related deaths outside Asia in 2050, despite comparable population-weighted PM2.5 exposure in the US and Europe. 

The key takeaway is that in addition to retiring coal plants, retiring them strategically could save a lot of lives.For the researchers, strategic power plant retirements, either performance-based or early retirements, would especially help in low-income and emerging economies whose power-generating units are still young but which tend to have smaller generating capacities, lower efficiencies and higher pollution emissions per unit capacity.  

For example, in China and India, 77,200 and 136,100 PM2.5-related deaths in 2030 could be avoided by early retirement and replacement of generators, respectively. Strategic power plant retirements under an ambitious climate scenario with strong pollution control would entirely eliminate the identified super-polluting units by 2030. 

The study was published in the journal Nature Climate Change.