Study shows Beijing haze linked directly to gaseous pollutants from traffic, industrial emissions

Study shows Beijing haze linked directly to gaseous pollutants from traffic, industrial emissions
Campus view of Peking University on clean and polluted days. Credit: Song Guo and Min Hu, Peking University.

( —A combined team of researchers from the U.S. and China has found a direct link between gaseous pollutants from motorized vehicles and industrial emissions and the thick haze that often covers the Chinese capital. In their paper published in the Proceedings of the National Academy of Sciences, the team describes their study which included taking air samples over a long period of time and what they found in analyzing the data.

Most people have heard of the air pollution problems going on in China—the country is home to 16 of the 20 most polluted cities in the world. Getting the most attention, has been Beijing, the country's capital and host of the 2008 summer Olympics. In this new effort the joint research team sought to better understand why Beijing, and perhaps other Chinese cities have such serious air pollution problems.

It doesn't take much looking to find that the pollution in Beijing comes mostly from cars, coal fired utility plants and other manufacturing and industrial operations. But, the team noted, taken together, they didn't appear to account for the level of haze that covers the city on a periodic basis. To learn more, they used new state-of-the-art equipment to take from October to December of last year.

In studying the data, they found that the amount of (the basis of haze) was more than was produced by the primary sources. Further study revealed that photochemical oxidation of gaseous pollutants was resulting in the formation of fine particulates, adding to the overall amount. Furthermore, they found that atmospheric conditions played a larger role in the development of heavy haze days than was previously thought. Wind, they noted, carried pollution from the south, where there are many coal fired plants, to the city, causing higher levels of haze. It also accounted for the cyclic nature of days in the city. Also, the team noted that there were fewer heavy hazy days in the summer because the city gets more rain then which tends to clean the air.

The researchers believe their findings are likely applicable to other cities in China and suggest that the only way to solve the air pollution problems in that country is to reduce the amount of pollutants emitted into the air.

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More information: Elucidating severe urban haze formation in China, PNAS, by Song Guo, DOI: 10.1073/pnas.1419604111

As the world's second largest economy, China has experienced severe haze pollution, with fine particulate matter (PM) recently reaching unprecedentedly high levels across many cities, and an understanding of the PM formation mechanism is critical in the development of efficient mediation policies to minimize its regional to global impacts. We demonstrate a periodic cycle of PM episodes in Beijing that is governed by meteorological conditions and characterized by two distinct aerosol formation processes of nucleation and growth, but with a small contribution from primary emissions and regional transport of particles. Nucleation consistently precedes a polluted period, producing a high number concentration of nano-sized particles under clean conditions. Accumulation of the particle mass concentration exceeding several hundred micrograms per cubic meter is accompanied by a continuous size growth from the nucleation-mode particles over multiple days to yield numerous larger particles, distinctive from the aerosol formation typically observed in other regions worldwide. The particle compositions in Beijing, on the other hand, exhibit a similarity to those commonly measured in many global areas, consistent with the chemical constituents dominated by secondary aerosol formation. Our results highlight that regulatory controls of gaseous emissions for volatile organic compounds and nitrogen oxides from local transportation and sulfur dioxide from regional industrial sources represent the key steps to reduce the urban PM level in China.

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Citation: Study shows Beijing haze linked directly to gaseous pollutants from traffic, industrial emissions (2014, November 25) retrieved 23 October 2019 from
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Nov 25, 2014
Wow, I just made this comment elsewhere. I guess I cite this for emissions other than CO2 from China, and every other country that doesn't burn fossil fuel cleanly. Soot, incompletely combusted hydrocarbons and other brown stuff, is nothing new just because we don't see it in concerned countries. Anyone can do the math on how much a dark broad spectrum absorber is more powerful than CO2 or even H2O.
I just got back from a micro tour of the world, and let me tell you, this kind of stuff trumps CO2 to.
Stop chasing the wild geese.

Nov 25, 2014
Of course it's worse than CO2, but both soot and co2 are as ephemeral as gauze. Where are the legendary London fogs? Gone. Standing in Hollywood, can you see the San Gabriel Mountains? Yes. You couldn't 40 years ago.

Peiping will figure it out eventually.

Nov 25, 2014
Ah, but it is not just Peiping. It's the Middle East, Afrique, probably everywhere without pollution laws.

Nov 25, 2014
I'll bet some of it is cigarette smoke.

Dec 06, 2014
Where are all the CO2 proponents?
Cowering like kittens as usual, pretending they didn't read this article, so they don't have to admit CO2 is a lie they've been fed to distract them from why the Earth is really changing.

Dec 06, 2014
Are you folk arguing there is no link between GDP and CO2 emissions?

Dec 06, 2014
No, as far as I know, I am the only violin playing in this mad mad CO2 blaming world.

Certainly there is a link, but increase in CO2 is more from the destruction of our ocean's ability to sink CO2, than any new production. Only 30 years ago, our oceans had more capacity to sink CO2 than we could possibly produce. Making it a great red herring for the climate debate.
But the theatrically named, but real phenomenon of "Dead Zones," spited that entire ruse.

CO2, is of course a weak player in a weak phenomenon.
What warms the Earth:
The Sun.
The Earths rotation.
The atmosphere.
The vertical mixing of the atmosphere.
The horizontal mixing of the atmosphere, responsible for weather effects, equator to pole heat transfer, etc..

These effects bring us very close to what we know as normal.
The next most powerful is evaporation/condensation, about 90x more powerful than GHG.
Now wiki will tell you that GHG are broken up between water vapor and CO2, about 70/30. Tiny.

Dec 06, 2014
" I am the only violin playing in this mad mad CO2 blaming world."

Ah, . . . a version of Nero's lament!

Dec 06, 2014

"It is not true that Nero fiddled while Rome burned. The fiddle hadn't been invented yet. He played the lyre and sang 'The Fall of Troy.'" -Will Cuppy, great historian

My motivations, as mad as they may be, are quite the opposite of Nero's. I am trying to get people to see through the BS behind Global WARMING, and see the primary effects of anthropomorphic change for what they are.

Warming, is a secondary effect. The primary effects are on the Earth's hydrodynamic cycle. Melting ice, black-body absorption, water, etc.. When these are peaked we'll see some warming.

I start with physical principles, apply them an am able to describe the effects we see and have been seeing for years. What I say may be inaccurate or out of scope, but it is never, and can't be, wrong.

Dec 06, 2014
" What I say may be inaccurate or out of scope, but it is never, and can't be, wrong."

You stole that from L Ron Hubbard.

Dec 07, 2014
I've never read L Ron..., is that good or bad?

Dec 07, 2014
It's a joke. He was a second-rate science fiction writer who realized he could make a lot of money in making fork think they were special. I first heard of him in a softcover version of "Great Swindles of the 20th Century", talking about Dianetics and Scientology, his invention to make himself rich and pay no taxes on it. It was big in Hollywood early in the era, then got exposed as a hoax by its second-in-command. But it arose, with q new generation of gullible folk with the need to be "special".

Unfortunately, if you are telling folk they are special and you can give them the ability to travel the universe at will, they will pay dearly for it. Even if they never get it.

Dec 13, 2014
Let's see if I can pull an original Water_Prophet in response to the Scientology:

Ye denounce me as a false prophet among those who would profit.
And so you can always see the false from the true by looking at their motive.

Nope, ran out of steam, I just don't have the same prose.

I guess I should be flattered with the comparison to my persuasive skills (?), but lets face it, I do simply use physical constants, properties and logic.

All the citations in the world can't put out the light of that candle. Saint Francis of Assisi

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