Those Soot Clouds in China Are from Automobiles and Home Cooking

For over a decade now, it has been clear that cooking with coal is causing big health problems in China. Indoor air pollution from solid fuel use in China is responsible for approximately 420,000 premature deaths annually, according to a 2007 study. But the impact wafts out of the kitchen to the outdoors too. Research released this week implicates coal cooking as a source of black carbon, and one of the causes of the infamous brown hazes that hang over East Asia.

Using a carbon-14 identification method, researchers from China, South Korea, America and Sweden traced four-fifths of the black carbon emitted in China to incomplete combustion of fossil fuels, such as coal briquettes used in home cookstoves and automobile and truck exhaust.

When one of the estimated 423 million people in China who use high-polluting stoves cooks, or when someone drives a diesel truck, black carbon is emitted in the form of fine particles. When the particles get into lungs, they can lead to respiratory problems like lung cancer. When black carbon gets into the atmosphere, it traps sunlight, combining with organic carbon and forming soot. Scientists think its contribution to global warming is behind only CO2.

In America, the 7th largest black carbon emitter in the world, most of our black carbon emissions come from transportation, from diesel engines and vehicles, and from wildfires.

As its air quality has become something of an international embarrassment, China has made efforts to ban coal stoves in urban areas, replace coal heaters in Beijing, and raise vehicle emission standards. At the same time, the number of cars on the road has risen.

The consensus so far seems to be that air in China is getting cleaner, but is far from clean. In January the US Embassy in Beijing reported that the air had a concentration of fine particles that was 35 times the World Health Organization's recommended standard for air quality.

Efforts to clean Chinese air begin in the wealthier parts of the country—the city centers–and move outward. For the estimated 8 million people in China who lacked electricity as recently as 2009, the best improvement to their air can come from getting better chimneys and more efficient stoves, which helps indoor air quality, but not outside.

In perhaps the ultimate boondoggle, even if everyone in China switches to electric stoves, guess where that electricity is coming from: probably from one of China 620 coal-burning power plants, which produce 79 percent of its electricity. Demand for electricity in China is estimated to triple by 2030, and over the same span demand for coal will double.

Optimists might say that cleaner burning coal power plant could at least cut down on black carbon emissions, which is nice, but still results in the release of CO2 into the atmosphere, but given that CO2 is heating our planet, it sort of feels like finding a silver lining on a visible red haze.