Wuhan’s Yellow Smoke Shows Public Mistrust

On Monday, Wuhan was covered in a thick yellow fog as levels of 10-micron particulate matter (PM10) climbed to peaks of over .6 milligrams per cubic metre, four times the national daily average. The cause of the extreme pollution was at first no clearer than the air itself. Rumours, unlike some expiring birds, flew; the city’s French consulate issued and then withdrew an advisory statement which mentioned a possible industrial chlorine leak. At Bloomberg, Adam Minter explored some of the various theories:

Two theories on the deadly smog soon emerged. The most popular, and the least serious, was that Wuhan’s high school students were burning their books in the wake of graduation and the much-hated college entrance examination. The more serious was that a large-scale industrial accident had taken place. Boiled Universe, the handle of a Wuhan-based Sina Weibo user of no great importance, was one of hundreds of microbloggers who offered a variation: “It’s said that a boiler explosion at Wuhan Iron & Steel caused large volumes of toxic dust and smoke to spread, enveloping the whole of Wuhan, and the death of two people.” Others not only promoted the rumor, they did so by re-tweeting what they claimed was a photo of a chlorine gas leak at Wuhan Iron & Steel. (Another microblogger later offered definitive proof that the photo was six months old).

Someone from Wuhan Iron & Steel Co. Ltd, clearly incensed by the rumor-mongering, logged into the company’s Sina Weibo account (the company has 900 followers, billions in revenue) to deny responsibility for the haze . But that was destined to go nowhere: Few in China are going to take the word of a giant state-owned steel company, especially when it comes to rumors about large industrial accidents. By mid-afternoon, fears of a chlorine gas leak had become so prevalent (online, at least), that the Wuhan Fire Department felt compelled to tweet on Sina Weibo to inform its 95,000 followers that over the course of Monday, it had removed two hornet’s nests, caught a snake and put out five small fires, but it had not, under any circumstance, responded to a major alarm, much less a “so-called chemical leak and explosion.”

Local authorities then went further. From Bloomberg, the following day:

Police in the Chinese city of Wuhan detained two people for spreading rumors that heavy pollution in the capital of Hubei province was caused by an industrial accident, a newspaper controlled by the local Communist Party reported.

The Changjiang Daily, supervised by Wuhan’s party committee, said government departments denied rumors the smog that covered the city June 11 was related to an industrial accident or the leaking of toxic gases. The newspaper didn’t give more information about the people detained or the rumors.

After some investigation, Wuhan’s Environmental Protection Bureau blamed burning of straw by farmers for the pollution, in a statement translated and circulated by the US embassy in Beijing:

An analysis of the air indicates the pollution is caused from burning of plant material northeast of Wuhan.

[…] According to our investigation, the abnormal air quality in our city is mainly caused by the burning of the crops northeast of Wuhan towards Hubei province. Similar air quality is occurring in Jiangsu, Henan and Anhui provinces, as well as in Xiaogan, Jingzhou, Jingmen and Xiantao, cities nearby Wuhan.

The straw burning explanation was, as Minter described, greeted with some incredulity. Farmers had long burned straw as fuel, but Monday’s pollution was exceptional, and its intensity seemed to point to an industrial source. But according to Cornell University air quality expert Dane Westerdahl, America’s only source of “beyond index” pollution scores is not industrial activity, but forest fire. Using straw as fuel spread the burning out over many months. With coal and natural gas replacing it in this role, and other traditional uses also disappearing, straw is now incinerated in vast quantities simply for disposal, producing greater, more concentrated amounts of smoke than in the past. Jiang Gaoming described this shift in a 2007 article at chinadialogue, pointing out that with some organisation and investment, the straw could instead be used to produce beef, fertilising manure or carbon-neutral energy.

In northern China it is now the middle of the autumn planting season, and once again the farmers are burning off the crop stubble left after the harvest. The highways that run through the fields are covered in smoke, which seeps in through closed windows and can reduce visibility to half a kilometre. It gets worse at night; crop fires are illegal, so the farmers wait till it gets dark to avoid getting caught. However, you were unlikely to see this a decade ago ….

So why are the farmers so determined to burn off their leftover straw? Because there is nothing else to do with it. In the past the straw was used as fuel, but now farmers are more affluent and burn coal or natural gas. At one time it could also have been used to feed draught animals, but now they have been replaced with tractors. The government has promoted the use of straw in methane production, but to date only 0.5% of China’s total 600 to 700 [million?] tonnes of straw produced annually is used to make the gas. Ideally it could feed livestock, but the cost of storing straw and the livestock itself makes this unfeasible. Even if you fed the entire nation’s herds with straw, there would still be a lot left over. One could increase the number of ruminants, but China’s straw is scattered around the country and the cost of collecting and transporting it is high. If farmers cannot make a decent profit from it (and they no longer care about earning a few yuan here and there) it will be burnt off to prevent it getting in the way of other work.

The immediate grab for explanations involving hushed-up accidents, and the widespread rejection of the one offered by the local government, show the depths to which trust on public safety issues has sunk. New rules requiring publication of PM2.5 data for cities around China, overdue or not, were a sign of progress on this front. More recent developments such as the arrests of the alleged rumour-mongers in Wuhan and demands for the US embassy to stop tweeting its own air quality measurements seem to indicate a backward step. At chinadialogue, Greenpeace’s Zhou Rong argued that, while the American @BeijingAir monitor does indeed accentuate negative readings, silencing it is not a solution. Instead, the government’s best means of overcoming public scepticism is greater transparency.

First, the government should face up to the severity of the air-pollution problem. China has long looked to traditional pollutant indicators like PM10 (coarse particulates) to evaluate air quality, but not PM2.5 levels. The result is a picture of air pollution that is, at times, too rosy – and out of step with public perceptions.

[…] Second, although most Chinese cities have now started to publish PM2.5 figures – a major step forward – they remain evasive about the health implications of that data. The public don’t understand what a daily average PM2.5 figure of 35ug/m3 or 75ug/m3 means for their health. They just want to know if their elderly parents can go out for a stroll or their kids can go out to play, but the raw statistics they are given don’t tell them that. In the absence of more “human” data, it is hardly surprising that so many citizens, concerned about their families, turned to the US embassy’s feed and its depressing litany of warnings – exaggerations that have worsened the fear and mistrust of the government.

It isn’t complicated stuff. But escalating it to a political – even a diplomatic – issue may just make it so. To regain public trust, all that the Chinese government needs to do is push its existing systems of data disclosure further, and provide accurate information in a format the public can digest and use. Breathing air under the same piece of sky every day, ordinary Chinese people make their own judgements about the state of their environment. And when it comes to statistics, urban residents will judge their veracity by their own experience.