The smog-enveloped Chinese capital of Beijing is still holding its breath during its first-ever 72-hour pollution red alert. The city's 22 million inhabitants are being advised to stay indoors if possible due to concerns they'll be exposed to hazardous levels of microscopic-sized particles that can penetrate deep into the lungs and lead to ailments such as heart attack, stroke, lung cancer and asthma.
The Air Quality Index, a measure of those particles, reportedly soared to over 600 and was still at close to 300 at midnight Wednesday Beijing time, according to according to measurements taken by the U.S. Embassy. Even that reduced level is many times the safe limit of 25 recommended by the World Health Organization.
But the pollution crisis is really just the latest episode in a longtime problem that Chinese officials have been trying to solve. And paradoxically, the public alert, which also included measures such as shutting down factories and taking half of the city's cars off the streets with an odd-even license plate system, actually may be a sign of progress.
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"There was a decision made to disclose more information about air quality, and raise public awareness," explains Alex Wang, a law school professor at UCLA, and the former director of the Natural Resource Defense Council's China Environmental Law and Governance program. "This is a contrast to five or 10 years ago, when people would look up at the sky and think it was just fog, rather than harmful pollution."
Beijing's longtime pollution problems are a combination of geography, rapid economic growth and longtime lack of pollution controls, experts say. The massive city is surrounded by mountains that help to trap emissions from factories and automobiles–and from the coal-fired boilers that many residents still rely upon for heat.
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"In the winter, the heating goes on, and that creates even more pollution," explains Alex Wang. And in addition to the city's own output, it's plagued by pollution that drifts through the atmosphere from factories in surrounding provinces.
The result is a city that between 2008 and 2015 averaged a daily AQI of 100, four times above the healthy limit. The continually foul air is a pressing public health problem. A 2014 study by Harvard researchers, for example, found that high exposure to particulates significantly reduced lung function in Beijing residents.
But when the pollution soars above the 250 level, as it is doing now, the threat is magnified. Richard Muller, scientific director of Berkeley Earth, a nonprofit research organization which has analyzed data from Chinese pollution monitoring stations, has described it as being the equivalent of smoking one-and-a-half cigarettes every hour.
"Right now, there's an enormous health hazard," says Dr. Norman Edelman, a senior scientific advisor to the American Lung Association. "Anyone with chronic lung disease or heart disease is going to be made worse."
Dr. Edelman says that staying indoors reduces the health risk from pollution for Beijing residents, but doesn't completely eliminate it. "You can't seal your house completely," he explains. "You need to have some fresh air come in." The Chinese practice of wearing masks outdoors, he says, is "not likely to offer much protection," because the material is too porous to filter out the fine particles or ground-level ozone, another pollution risk.
But the alert is just part of the long-term effort to fight Beijing pollution. City and regional officials started getting serious about curbing pollution in 2013, Wang said, after a smog crisis far worse than the present one. In that event, the AQI reportedly soared to as high as 886, a level so high that it's off the U.S. Environmental Protection Agency's charts.
Since then, Wang notes, Bejing has been on a multi-year plan, which includes measures such as installing better pollution controls at factories, moving some facilities outside the city, getting older vehicles with dirtier exhaust off the roads and switching residents to gas heat. In 2014, Beijing even enacted its first tough pollution-control law, with targets for reducing emissions and heftier fines for polluters. The new measures also include a pollution alert system to warn residents to take protective measures when the air is unhealthy.
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But Wang notes that until the recent crisis, pollution levels had been slightly decreasing in 2015–a sign that the government's program was starting to see at least modest results. The smog alert highlights the need to accelerate those measures, he says.
In the long term, Beijing's pollution woes may be reduced by economic change. "They want to move away from heavy industry, steel and cement, that require a lot of energy and emissions, and move toward services, tourism and technology, which can generate GDP without a lot of pollution," Wang explains.
But in order to clear the air, that evolution will have to spread to surrounding provinces as well. Scientists from Berkeley Earth, who've analyzed data collected by Chinese pollution monitoring stations, have found that distant industrial areas such as Shijiazhuang, which is 200 miles to the southwest, contribute to Beijing's smog. That all adds up to a vast pollution program which, according to Berkeley Earth's calculations, exposes nearly 4 out of 10 Chinese to unhealthy air, and causes 1.6 million deaths each year.
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China's pollution -- along with emissions from other Asian countries, including India -- so intense that it even can affect U.S. weather, according to Jonathan H. Jiang, a scientist with NASA's Jet Propulsion Laboratory in Pasadena, Calif. who has studied the phenomenon.
Jiang explained that under certain conditions, pollution particles from places such as Beijing can be lifted up high into the atmosphere, so that the jet stream -- a giant river of fast-moving air -- can transport them across the Pacific Ocean. "If that happens, our model indicates that it can intensify the storm track here," he said.
But Wang is hopeful that Beijing and other Chinese cities eventually will be able to cut their pollution. "I feel that within the next decade, you could see significant improvement," he says.
That pollution also has an impact upon the dynamics of the Earth's atmosphere, affecting even larger-scale weather patterns across the globe, Jiang said. (Fortunately, the Chinese particulate itself doesn't descend to ground level here.)