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Smog in the Western U.S.: Blame China?

air pollutionchina pollutiongreenhouse gasesozonesmog
China traffic Ozone from Asia is wafting across the Pacific on springtime winds and boosting the amount of the smog-producing chemical found in the skies above the Western United States, researchers said in a study released Wednesday.

The study, published in the journal Nature, probes a phenomenon that has puzzled scientists in the last decade: Ground-level ozone has dropped in cities thanks to tighter pollution controls, but it has risen in rural areas in the Western U.S., where there is little industry or automobile traffic.

The study, led by Owen R. Cooper, an atmospheric scientist at the University of Colorado, examined nearly 100,000 observations in the free troposphere — the region two to five miles above ground — gathered from aircraft, balloons and ground-based lasers.

It found that baseline ozone — the amount of gas not produced by local vehicles and industries — has increased in springtime months by 29% since 1984. The study has important implications both for the curbing of conventional pollution that damages human health and for controls on greenhouse gases  that are changing the planet’s climate, experts said.

It shows the need, said Mary Nichols, chairwoman of the California Air Resources Board, for a transformation of global energy and transportation systems. “Atmospheric scientists keep finding more evidence that pollutants travel around the globe and move up and down as they travel,” she said. “There is not a bright line separating greenhouse gases from regular air pollution.”

The study, co-authored by researchers from nine institutes in the U.S. and abroad, is only a first step in understanding the complexities of cross-border pollution, Cooper said. More research will be needed to probe the sources of ozone at ground level and at other times of the year. The researchers began with the free troposphere because it is easier to eliminate local sources from baseline ozone calculations. They chose the months of April and May because that is when winds from Asia are strongest.

“Ozone is a difficult gas to pin down,” said Cooper, who works at the Earth System Research Laboratory  of the National Oceanic and Atmospheric Administration in Boulder, Colo. “The study of intercontinental air pollution has been going on for a decade, but whether it was increasing overall was uncertain. And in places where it had spiked, along coasts and in national parks, we didn’t know how much was from local sources and how much was from Asia.”

Cooper said they have not yet determined exactly how much of the ozone increase comes from Asia, but they found that the increase was about twice as much when prevailing winds came from South and East Asia.

Still, the new study offers “the most conclusive evidence so far of increasing ozone levels in the free troposphere over North America,” wrote atmospheric chemist Kathy Law, an expert in long-range pollution transport, in a Nature commentary on the paper.

Moreover, she added, the increases “certainly have implications for climate change, causing warming
either at the mid-latitudes where ozone forms, or in sensitive regions such as the Arctic to which ozone
might be transported.”

According to the U.S. Environmental Protection Agency, ground-level ozone is linked to serious health problems, ranging from aggravation of asthma to increased risk of premature death in people with heart or lung disease. In Southern California, which has some of the highest pollution levels in the U.S, smog levels exceed health standards more than 80 days a year. Based on new studies, the EPA announced this month that it might tighten federal ozone rules.

Ozone is not the only substance that crosses borders. Last year, a study by the National Research Council found that “significant concentrations” of three other types of air pollutants are also transported across the Northern Hemisphere: particulate matter such as dust, sulfates or soot; mercury; and persistent organic pollutants such as DDT. Emissions of nitrogen oxides, a key ingredient for ozone formation, have increased by more than 50% in China over the last decade while decreasing in the U.S. and Europe.

The issue is also of concern to U.S. industry, which is chafing under domestic controls. A 2006 petition
from the U.S. Chamber of Commerce on fine particulate pollution asked the EPA “to develop national
regulations to clarify how states and localities should address the impact of international transport in air quality planning.”

-- Margot Roosevelt

Photo: Beijing traffic. Credit: AFP/Getty Images

Comments () | Archives (12)

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The idea of an ozone and global warming is an urban myth! Don't believe anything you hear, I tell you!!!!


Have you ever taken a physics class? Do you understand just how dense uranium is - depleted or not? What makes you think that a material that is about twice as dense as lead will float very far in the air?

The story here is that the noxious waste products produced by burning fossil fuels and dumped into the atmosphere float around and end up far from their dumping grounds. As someone who lives downwind of coal burning areas in West Virginia and Ohio, I see the effects of the same kind of transport with some of the dirtiest air in the US even though my state is actually pretty clean with regard to its own emissions.

Don't try to turn the story into a cry against nuclear energy, the only real choice that we have to burning fossil fuels if we want reliable power.

Rod Adams
Publisher, Atomic Insights
Host and producer, The Atomic Show Podcast

Baloney. If China were the culprit then why does Honolulu bring in highest marks for good air quality year after year? Find another demon. China isn't the cause.

More good news. That depleted uranium the USA is blasting all over the world, is also blowing in the wind and ends up back in the USA among others.

As for the pollution from China, maybe if the USA actually still had some industry of their own, and didn't have to buy everything from China...

Well, what? Is this a surprise to anyone? U.S. corporations lobbied hard so that they could move production and good paying U.S. jobs to countries with slave labor laws and no environmental protections. Now they've destroyed the middle class, super-sized their profits and caused ecological disasters over the globe.

The Chinese were just happy to get jobs, any kind of kind of jobs, but the real culprits here are not the Chinese, it's the greedy fat-cats with their multi-million dollar lobbying budgets that get any law passed or repealed they want.

Welcome to the corporate-run Earth, no job security, a collapsing economy, totally corrupt politics and a rapidly dying global life-support system.

And they always tell us we're better off this way...

Hannah Holmes wrote about this is a great book called, "The Secret Life of Dust." in 2001!

All of that cheap stuff from Walmart, et al that we just MUST have is being produced in pollution belching factories. I would be happy to pay the higher prices for domestically produced items that are produced in an environmentally way. Would you?


I loled when I read your question:

when will we hold China accountable for anything?

since I was asking the almost identical question after reading the article, except changing "will we hold" to "has the media held?"

When I read something, is it me or some stupid editor who expresses an opinion?

Info on research results, partially passed to me. Title and the stupid question, back to the editor.

Blame it on chemtrails. They are spraying the west coast constantly. Look up and wake up!

Much of the coal going to China, is coming from the Western United States. So we should stop exporting coal out of places like Alaska and Wyoming to simply have China burn it and send the pollution back to us.

Let me get this straight. We outsource our factories to China, they make the stuff that fills our Wal Mart shelves, and they emulate our car-dependant urban form, and WE blame THEM?! Are you serious?

We're breathing our own pollution, it just comes from farther away now.

eye opening. when will we hold China accountable for anything?

still, I think her reference to 'greenhouse gases' comment was ridiculous. OK sure CO2 can move around the globe, but global warming seems to be quite an impressive hoax perpetrated by Al Gore and others at this point.


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