A hard rain is falling as acid erodes beauty
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Cutting emissions
The sad findings of that report suggest the country has failed to curb environmental deterioration despite huge anti-pollution efforts, said Wei Fusheng, an academician at the Chinese Academy of Engineering.
His comments echo the growing public complaints about worsening air quality in many major cities.
Last month, Beijing's municipal government announced it had hit its target of 266 "blue-sky days" in 2010 ahead of schedule. However, the usual thick smog and the smell of smoke during winter - when the central heating system is fired up - made some citizens doubt the accuracy of the capital's air quality ratings. Similarly, in the Yangtze River and Pearl River deltas, more hazy days are recorded every year.
"That shows the existing monitoring and assessment systems for the country's environmental quality have their defects," said Wei, who added that, for one thing, nitrogen oxides and other pollutants are still left out when it comes to emissions control.
Nitric oxide (NO) is mainly derived from road transport emissions and combustion processes, such as the electricity-generating sector. It can rapidly be oxidized to nitrogen dioxide (NO2) once released to the atmosphere. Together, they are referred to as nitrogen oxides (NOx).
NO2 can irritate the lungs and lower people's resistance to respiratory infections, like influenza. Continued exposure to higher concentrations can also cause increased incidence of acute respiratory illness in children. "It is impossible to cure haze and acid rain problems in large cities without addressing pollution with nitrogen oxides," said Yang Jintian, deputy chief engineer at the Chinese Academy of Environmental Planning.
In China, coal-fired power plants are major sources of nitrogen oxides and contribute 45.5 percent to total emissions. In 2008, emissions reached 20 million tons, the largest in the world, said Yang.
As the world's biggest automaker and consumer of automobiles since 2009, China's vehicle exhaust fumes are major contributors to air pollution.
A joint study by scientists from Tsinghua University, Harvard University and the Norwegian Institute for Water Research, which was published in the American Chemical Society's Environmental Science and Technology journal in 2009, concluded that the benefits of SO2 reductions in China can be offset by increased nitrogen emissions in a few years, if the country does not adopt a multi-pollutant control strategy that integrates measures to reduce sulfur, nitrogen and particulate matter.
Daunting challenges
Environmental authorities announced that in the upcoming 12th Five-Year Plan (2011-2015), China will include two more pollutants - nitrogen oxides and ammonia nitrogen, which leads to excessive nutrients and causes algae outbreaks in water - under its mandatory pollution-control program.
The new target proposed by the Ministry of Environmental Protection is to slash both pollutants by 10 percent in the next five years.
For sulfur dioxide and chemical oxygen demand, which is a measurement of water pollution, the new reduction goals will be set at about 8 percent, slightly lower than the 10-percent target between 2006 and 2010, according to a source with the Ministry of Environmental Protection who did not want to be identified discussing policy that has not yet been approved.
The proposal is still awaiting clearance from the State Council, with a final decision expected in March during the annual two sessions of the National People's Congress and the Chinese People's Political Consultative Conference.
The ministry official admitted China will face even more pressure to achieve its air pollution control targets, considering its expanding appetite for coal consumption.
Tao Wang, an atmospheric chemist at Hong Kong Polytechnic University, said nitrogen emissions are more difficult to curtail than sulfur. Whereas sulfur-scrubbing technology can reduce emissions at power plants by about 90 percent, nitrogen-control technologies such as low-NOx burners typically only achieve 10 to 60 percent efficiency, he explained.
Technologies that can produce 85- to 90-percent reductions in NOx are available, but they are still too expensive and not yet widely used in China.
Bosses at several power plants visited by China Daily reporters complained the original designs of their facilities do not allow physical space to install new equipment. To meet the new pollution control targets will require them to completely revamp their plants.
It will be even more difficult to deal with the nitrogen emissions from vehicles, which remain a worldwide challenge.
There is already little room left for China to further slash sulfur emissions, said the ministry source. By the end of 2009, about 71 percent of coal-fired power plants had been equipped with sulfur scrubbers, compared to 12 percent back in 2005. "The next step is to take a closer look at whether these facilities are actually put into use," he said.
The ministry official admitted the biggest challenge remains China's enormous coal consumption, which is set to grow at a relatively high rate during the coming years to fuel the country's economic growth. "Studies by some experts have suggested that burning 3 billion tons of coal every year would be the upper limit if we want to keep the sulfur and nitrogen emissions to a reasonable level," he added.
Despite the central government's pledge to rely more on renewable energy sources, Wang Xianzheng, president of the China National Coal Association, recently projected annual coal consumption will reach 3.8 billion tons by 2015, an increase of 800 million tons compared to 2009.
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