SHENZHEN, China — In this sprawling metropolis in southeastern China stand two hulking brown buildings erected by a private company, the Longgang trash incinerators. They can be smelled a mile away and pour out so much dark smoke and hazardous chemicals that hundreds of local residents recently staged an all-day sit-in, demanding that the incinerators be cleaner and that a planned third incinerator not be built nearby.
After surpassing the United States as the world’s largest producer of household garbage, China has embarked on a vast program to build incinerators as landfills run out of space. But these incinerators have become a growing source of toxic emissions, from dioxin to mercury, that can damage the body’s nervous system.
And these pollutants, particularly long-lasting substances like dioxin and mercury, are dangerous not only in China, a growing body of atmospheric research based on satellite observations suggests. They float on air currents across the Pacific to American shores.
Chinese incinerators can be better. At the other end of Shenzhen from Longgang, no smoke is visible from the towering smokestack of the Baoan incinerator, built by a company owned by the municipal government. Government tests show that it emits virtually no dioxin and other pollutants.
But the Baoan incinerator cost 10 times as much as the Longgang incinerators, per ton of trash-burning capacity.
The difference between the Baoan and Longgang incinerators lies at the center of a growing controversy in China. Incinerators are being built to wildly different standards across the country and even across cities like Shenzhen. For years Chinese government regulators have discussed the need to impose tighter limits on emissions. But they have done nothing because of a bureaucratic turf war, a Chinese government official and Chinese incineration experts said.
The Chinese government is struggling to cope with the rapidly rising mountains of trash generated as the world’s most populated country has raced from poverty to rampant consumerism. Beijing officials warned in June that all of the city’s landfills would run out of space within five years.
The governments of several cities with especially affluent, well-educated citizens, including Beijing and Shanghai, are setting pollution standards as strict as Europe’s. Despite those standards, protests against planned incinerators broke out this spring in Beijing and Shanghai as well as Shenzhen.
Increasingly outspoken residents in big cities are deeply distrustful that incinerators will be built and operated to international standards. “It’s hard to say whether this standard will be reached — maybe the incinerator is designed to reach this benchmark, but how do we know it will be properly operated?” said Zhao Yong, a computer server engineer who has become a neighborhood activist in Beijing against plans for an incinerator there.
Yet far dirtier incinerators continue to be built in inland cities where residents have shown little awareness of pollution.
Studies at the University of Washington and the Argonne National Laboratory in Argonne, Ill., have estimated that a sixth of the mercury now falling on North American lakes comes from Asia, particularly China, mainly from coal-fired plants and smelters but also from incinerators. Pollution from incinerators also tends to be high in toxic metals like cadmium.