Hundreds of power plants in China responsible for spewing harmful pollutants have significantly curtailed their emissions, says a recent study.

The emission levels started coming down after the government introduced an ultra-low emissions (ULE) policy for renovating coal-fired power-generating units in 2014. The policy aims at limiting emissions of three major pollutants: sulfur dioxide (SO₂), nitrogen dioxide (NO_x) and extremely fine particulate matter (PM2.5 and 10). 

The technologies at the power plants were upgraded to meet SO₂, NO_x and PM emissions target of 35, 50 and 10 micrograms per cubic meters, respectively. An analysis by a team of experts from the UK and China found that between 2014 and 2017, SO₂ and NO_x emissions dropped by more than half. The PM levels have reduced by 72 percent.

The study titled, "Substantial emission reductions from Chinese power plants after the introduction of ultra-low emissions standards," published in Nature Energy journal on Tuesday, also predicts that China could potentially meet the 2020 emission target if all thermal power plants meet the ULE standards.

"These significant emission reductions demonstrate the technical and economic feasibility of controlling emissions from power plants to reach ultra-low levels, which is an important step towards reducing the number of deaths attributable to air pollution," Dr. Zhifu Mi, co-author of the study said.

According to the World Health Organization, pollutants from these power plants are responsible for causing irreversible health damages among residents. Recent studies also found air pollution adversely affects human productivity.

The study also found that previous studies overestimated emissions by Chinese power plants by at least 18 percent, and in some cases up to 92 percent. Researchers pointed out that the incorrect estimation happened as a result of using ex-ante studies – evaluations made ahead of the introduction of ULE standards – which looked at how the rules might affect emissions based on assumptions of changes in emission concentrations.

"The research is the first to use data on emission concentrations collected by China's Continuous Emission Monitoring Systems network (CEMS), which covers 96-98 percent of Chinese thermal power capacity," researchers said.

China's success in reducing emissions from the power sector can be a learning opportunity for other countries, Mi added. Globally, coal-fired thermal power plants, oil, natural gas and biomass are some of the significant reasons behind worsening air quality.