A new international study showing that pollutants from China are affecting air quality on the west coast of North America is partly payback for western consumers having their goods manufactured there, a University of B.C. professor said Wednesday.
鈥淲hy are they having these high emissions?鈥� asked Michael Brauer of the school of population and public health. 鈥淧art of it is the stuff they鈥檙e producing for us. Some of it is coming back to bite us ... through our consumption.鈥�
As more manufacturing has gone offshore over the years, so has the pollution. And some of that is wafting back here on the air currents.
鈥淚n a sense, we鈥檝e outsourced the problem to somebody else,鈥� Brauer said in an interview. 鈥淲e can鈥檛 just point a finger at China and say, 鈥榶ou guys clean up your act. You have this horrible pollution.鈥� We are actually part of the problem because we鈥檙e buying their goods.鈥�
West Coast residents should respond to the study findings by taking greater action to reduce pollutants in their own back yard, he said. 鈥淲hen we see the global background increasing ... we have to be that much more careful about our own contribution. That鈥檚 what we can control.鈥�
Brauer said the human health impacts are 鈥減retty minor鈥� with less than five per cent of Metro 91原创鈥檚 air pollutants on average coming from offshore, although that can increase to 25 per cent on certain days.
Events such as dust storms in the Gobi Desert and forest fires in Siberia can especially impact local air quality, he said.
Matt Dodd, an environmental analytical chemist at Royal Roads University in Victoria, explained that under a 鈥済rasshopper effect,鈥� pollutants get into the atmosphere then fall to earth when they hit colder weather. When conditions warm, they rise up again. Eventually, they settle in the Arctic and concentrate in the food chain, he said.
Dodd said that federal funding for monitoring of such pollutants dried up around 2010, quashing the university鈥檚 efforts to monitor for offshore air pollutants on 91原创 Island.
Danny Kingsberry, spokesman for Environment Canada, said it is estimated more than 95 per cent of the anthropogenic deposition of mercury in Canada is from foreign sources, with the East Asian contribution estimated at 40 per cent.
鈥淒etecting the effect of the recent pollution episodes very much depends upon the weather conditions over Asia and the jet stream pattern from there to North America,鈥� he said. 鈥淲ithout assessing such conditions using computer models, it is not possible to provide a definitive answer.鈥�
The study published in the Proceedings of the National Academy of Sciences is the first to quantify pollution reaching the west coast from the Chinese manufacturing sector that produces everything from mobile phones to televisions for global export, according to a statement about the study from the University of California, Irvine, where one of the authors is based.
Los Angeles sees at least one extra day a year of smog that exceeds federal limits because of nitrogen oxides and carbon monoxide emitted by Chinese factories producing for export, the analysis found. China鈥檚 economic ascent has been accompanied by a surge in pollution and the World Bank estimates that the Asian nation has 16 of the 20 most-polluted cities globally.
鈥淲e鈥檝e outsourced our manufacturing and much of our pollution, but some of it is blowing back across the 91原创 to haunt us,鈥� Steven Davis, a co-author of the study and an earth system scientist at the University of California, Irvine, said in the statement. 鈥淕iven the complaints about how Chinese pollution is corrupting other countries鈥� air, this paper shows that there may be plenty of blame to go around.鈥�
Winds called the 鈥渨esterlies鈥� can drive airborne chemicals across the ocean and lead to dangerous spikes in contaminants, according to the university鈥檚 statement. Dust, ozone and carbon may collect in valleys in California and other Western states, it said, while noting that China still isn鈥檛 responsible for the lion鈥檚 share of pollution in the U.S.
Jintai Lin of Beijing鈥檚 Peking University was the lead on the study and joined by experts at several global universities as co-authors.
In China, President Xi Jinping has pledged to tackle pollution amid rising public concern that smog and environmental degradation are affecting the nation鈥檚 health and the economy. The Ministry of Environmental Protection this month told all provinces and municipalities to cut air pollutants by as much as one quarter.
The Asian nation is the world鈥檚 largest emitter of anthropogenic air pollutants, according to the paper, with a fraction of its emissions caused by the manufacture of goods for foreign consumption. Anthropogenic pollutants typically refer to those originating from human activity.
In 2006, 36 per cent of anthropogenic sulphur dioxide, 27 per cent of nitrogen oxides, 22 per cent of carbon monoxide, and 17 per cent of black carbon emitted in China were associated with production of goods for export, according to the paper. For each of these pollutants, about 21 per cent of export-related Chinese emissions could be traced to U.S.-related exports, the paper said.
Black carbon, linked to conditions including asthma and cancer, is a 鈥減articular problem,鈥� according to the University of California statement.
On some days, the export-related Chinese pollution contributed to as much as 24 per cent of sulphate concentrations over the western U.S., according to the study.
More than 600 million people were affected in China by a 鈥済lobally unprecedented鈥� outbreak of smog in the country that started last January and spread across dozens of provinces, lasting several months, Ma Jun, the founder and director of the Beijing-based Institute of Public & Environmental Affairs, told reporters on Jan. 15.
鈥淎ir pollution doesn鈥檛 have boundaries,鈥� said Zhi Ning, an assistant professor at City University of Hong Kong鈥檚 School of Energy and Environment, who isn鈥檛 connected to the latest study. 鈥淚t can come from China to the U.S., but it can also go the other way.鈥�
With files from Bloomberg
