A New Atmospheric Villain

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A major turning point in China's campaign to lower pollution and increase energy efficiency appeared to have arrived in 2008.

That year, China released only 23.21 million tons of sulphur dioxide, a major atmospheric pollutant, into the atmosphere. This was almost a 9 percent decrease from 2005. If the trend continues, China will likely achieve a goal set forth in the Eleventh Five-year Plan for a 10 percent reduction in sulphur dioxide emission by 2010.

Sulphur dioxide is a primary ingredient in acid rain, which affects most of China's populated areas.

Unfortunately, China's reduction in sulphur dioxide emissions hasn't brought about a corresponding decrease in the potency of acid rain. This is likely due to rising levels of nitrogen oxides, a class of chemical pollutants that were not addressed in the emissions reduction plan.

According to statistics from 2003 to 2007 alone, China's emission of nitrogen oxides from power stations has increased by 40 percent. China's acid rain has already begun to transform from a sulphuric acid to a nitric acid composition.

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Yang Jintian, vice-chief engineer at the Ministry of Environmental Protection's Academy for Environmental Planning, told Caijing that the rise in nitrogen oxides has partially offset the positive effects of reduced sulphur dioxide emissions. For this reason, he said, it's important that nitrogen oxides are regulated as soon as possible

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The Dangers of Nitrogen Oxides

Nitrogen oxides present multiple risks in addition to acid rain. The compounds can irritate the human respiratory system, and contribute to excessive aquatic plant growth.

An expert in atmospheric pollution, Yang Jintian said, "If we don't solve the problem of nitrogen oxides, combating smog, acid rain, and other kinds of pollution will be next to impossible."

On October 1, 1996, China formally implemented the 《Ambient Air Quality Standard》, which set forth clear limits on atmospheric concentrations of nitrogen oxides and nitrogen dioxide. However, industry professionals believe that these standards were never strictly enforced. Excessive and unconstrained emission of nitrogen oxides persists in cities all over the country.

In 2000, the National Bureau of Environmental Protection (MEP), predecessor to the Ministry of Environmental Protection, revised these standards. Under the revision, limits on nitrogen oxides were completely eliminated, while the limits on nitrogen dioxide were greatly relaxed.

The official explanation for these adjustments was that they were consistent with international standards. For example, the United States began to measure nitrogen dioxide more carefully, rather than using the concentration of nitrogen oxides as an indicator of air quality.

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But this explanation has not received widespread credence. Tang Xiaoyan, an environmental professor from Peking University, told Caijing reporters that nitrogen dioxide encompasses only about 40 to 60 percent of all nitrogen oxide emissions. The United States chose nitrogen dioxide as the main indicator of air quality because existing observation stations were far outside cities. Most of what cities emit is nitrogen monoxide which converts to nitrogen dioxide only after it is dispersed into the atmosphere.

However, most of Chinese observation stations are built in city centers or within major traffic corridors. Factories and automobiles emit large amounts of nitrogen monoxide, which does not undergo conversion in time to be observed as nitrogen dioxide. Thus the "contribution" that nitrogen monoxide makes to atmospheric pollution is completely ignored in the new atmospheric standards. As a result, while Chinese cities meet overall standards for nitrogen dioxide emissions, this achievement is largely hollow.


For a variety of reasons, nitrogen oxides weren't included as a category for emissions reduction in the Eleventh Five-year Plan. Over time, however, they and the pollution they create are gaining more public attention.

On July 7, the MEP published emission standards for coal-fired power stations, requiring both new and existing power stations to comply with emission caps on nitrogen oxides set forth by the standards.

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Fossil-fuelled Breakthrough

At present, emissions from coal-fired power stations account for more than a third of the nation's total nitrogen oxide output.

According to MEP calculation, China's power stations will increase generating capacity to 1.2 billion kilowatts by 2020, twice as much as in 2008. Thus, without effective regulation, this means that the nitrogen oxides emission could increase by 70 percent from 2008 levels to 14.52 million tons.

Like sulfur dioxide, nitrogen oxides emissions vary widely by region. In eastern China, where most coal-fired power plants are concentrated, the problem is much more serious than in the economically underdeveloped west.

Tang Xiaoyan said that given these conditions, a regionally differentiated model of regulation would be more suitable. For instance, regulations could first be implemented in economically developed regions like the Pearl and Yangtze River Deltas and the Beijing-Tianjin zone, and later introduced in interior cities with pollution problems such as Wuhan, Changsha, Chongqing, Chengdu, and so on.

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Tang also told Caijing that some of the larger power generators must implement regulations "a step at a time – such a huge task can't be accomplished all at once."

China Power Industry Union, the China Huaneng Group, China Datang Corporation, and China Huadian Corporation have refused to comment with Caijing on the new nitrogen oxides emissions standards, saying the issue is too sensitive to discuss.

Tang said that the nationwide regulation on nitrogen oxides emissions provides only guidelines, rather than accurate, enforceable standards. The data remains unclear, he adds, making dialogue between regulators and industry problematic.

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Many experts believe that solving the current problem requires accurate statistics on the primary sources of emissions. Emissions limits must then be formulated, with standards for each type of industry. Limits for newly established companies must be based on the requirements and standards of the newest technologies, and strict limits must be placed in order to curb further emissions.

Power companies are currently being solicited for their opinions regarding regulation standards, and different regulations are already being drafted for both new and aging emitters.

Yang Jintian of the Chinese Academy of Environmental Planning stressed to Caijing that China is confronting several complex environmental pollution problems. Simply controlling sulfur dioxide and nitrogen oxides emissions as well as other lesser pollutants is not enough. Only with a comprehensive, well-established and organised regulatory body can China truly develop adequate standards and enforcement measures.