According to a report published by NASA, India's emissions of sulfur dioxide have risen dramatically. Sulfur dioxide (SO2) is an air pollutant that leads to acid rain, haze, and many health-related problems. It is primarily produced through the burning of coal to generate electricity.
The study by researchers from the University of Maryland and NASA indicated that although China and India remain the world's largest consumers of coal, the new research found that China's sulfur dioxide emissions have fallen by 75 percent since 2007.
China and India are now the world's top consumers of coal, which typically contains up to 3 percent sulfur. Most of the sulfur dioxide emissions come from coal-fired power plants and coal-burning factories. In particular, Beijing suffers from severe haze problems because of the factories and power plants located nearby and upwind.
But India's emissions have increased by 50 percent. The results suggest that India may soon become, if it is not already, the world's top emitter of sulfur dioxide.
Can Li, an atmospheric chemist at the University of Maryland, said, "The rapid decrease of sulfur dioxide emissions in China far exceeds expectations and projections." "This suggests that China is implementing sulfur dioxide controls beyond what climate modelers have taken into account," he said.
The maps show regional views of sulfur dioxide emissions as observed by the Dutch-Finnish Ozone Monitoring Instrument (OMI) on NASA's Aura spacecraft. The values are yearly averages of sulfur dioxide concentrations over India and China in 2005 and 2016. The data come from the study that was published on November 9, 2017, in the journal Scientific Reports.
2005: Sulfur dioxide levels in China
Starting in the early 2000s, China began implementing policies such as fining polluters, setting emission reduction goals, and lowering emissions limits. According to the new study, these efforts are paying off. Can Li says, "Sulfur dioxide levels in China declined dramatically even though coal usage increased by approximately 50 percent and electricity generation grew by over 100 percent." Courtesy: earthobservatory.nasa.gov
2016: Sulfur dioxide levels in China
The study suggests that much of the reduction is coming from controlling emissions. Previous studies, which relied on ground-based inventories and published policies, projected that China's sulfur dioxide emissions would not fall to current levels until 2030 at the earliest. Courtesy: earthobservatory.nasa.gov
2005: Sulfur dioxide levels in India
By contrast, India's sulfur dioxide emissions increased by 50 percent over the past decade. The country opened its largest coal-fired power plant in 2012 and has yet to implement emission controls like China. Courtesy: earthobservatory.nasa.gov
2016: Sulfur dioxide levels in India
Li said, right now, India's increased sulfur dioxide emissions are not causing as many health or haze problems as they do in China because the largest emission sources are not in the most densely populated area of India. However, as demand for electricity grows in India, the impact may worsen. Courtesy: earthobservatory.nasa.gov