Daily Current affairs
This week, air pollution forced some 4,000 schools to close in New Delhi, as India’s capital suffers through an air quality nightmare. Now, here’s more bad news on the pollution front: the country is passing China as the world’s biggest emitter of deadly man-made sulfur dioxide (SO2).According to a University of Maryland-led study published in Nature on Thursday (Nov. 9), China’s SO2 emissions have fallen 75% since 2007, while India’s emissions have increased 50% in the same period.
That puts India on track to overtake China, the world’s largest SO2 emitter since 2005—if it hasn’t already.India overtook the US in 2010 to become the world’s second-largest SO2 emitter, and became the world’s second-largest consumer of coal last year. Coal typically contains up to 3% sulfur by weight, and burning coal creates SO2, a toxic pollutant that contributed significantly to the 1952 London smog crisis that hospitalized more than 150,000, as well as the haze that hovers over many Indian and Chinese cities, stealing years from peoples’ lives.
China and India are the world's top consumers of coal, which typically contains up to three percent sulphur, researchers said.
Most of the two countries' sulphur dioxide emissions come from coal-fired power plants and coal-burning factories.
In particular, Beijing suffers from severe haze problems because of the many coal-burning factories and power plants located nearby and upwind.
Starting in the early 2000s, China began implementing policies such as fining polluters, setting emission reduction goals and lowering emissions limits.
According to the results of the current study, these efforts are paying off.
"Sulphur dioxide levels in China declined dramatically even though coal usage increased by approximately 50 percent and electricity generation grew by over 100 percent," said Li, who is also a research associate at NASA's Goddard Space Flight Center.
"This suggests that much of the reduction is coming from controlling emissions," said Li.
Despite China's 75 percent drop in sulphur dioxide emissions, recent work by other scientists has shown that the country's air quality remains poor and continues to cause significant health problems.
This may be because sulphur dioxide contributes to only about 10 to 20 percent of the air particles that cause haze, according to Li.
By contrast, India's sulphur 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, researchers said.
"Right now, India's increased sulphur 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," Li said.
"However, as demand for electricity grows in India, the impact may worsen," said Li.
To generate an accurate profile of emissions over India and China, the researchers combined emissions data generated by two different methods.
First, they collected estimated emission amounts from inventories of the number of factories, power plants, automobiles and other contributors to sulphur dioxide emissions.
The researchers' second data source was the Ozone Monitoring Instrument (OMI) on NASA's Aura satellite, which detects a variety of atmospheric pollutants including sulphur dioxide.