Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cooperative SO2 and NOx aerosol formation in haze pollution

29.01.2014
Air pollution in China has exhibited noticeable changes over the past 30 years, shifting from point-source pollution (around factories and industrial plants) in the 1980s to urban pollution in the 1990s.

Since the start of this century, air pollution has become increasingly regional and more complex. Recent research has indicated that the cooperative transition of SO2 and NOx into secondary aerosols (sulfate and nitrate) played a critical role in the haze pollution episode in China in January 2013.


This shows a) particle number size distributions and b) fractional contributions of organics, nitrate, sulfate, ammonium, and chloride to the PM1 mass during the haze episode from 06:00 to 15:00 LT, Jan. 12, 2013.

Credit: ©Science China Press

The coexistence of high concentrations of primary and secondary gaseous and particulate pollutants results in numerous heterogeneous reactions occurring on the surfaces of fine particles. These reactions change the oxidizing capacity of the atmosphere, chemical compositions, and the physicochemical and optical properties of the particulate matter. The overall effect is that air pollution and haze formation is accelerated.

It is, therefore, important to explore the formation mechanisms of secondary aerosols during air pollution episodes. The paper, "Mechanism for the formation of the January 2013 heavy haze pollution episode over central and eastern China", Science China: Earth Sciences, No. 1, 2014, by Professor Wang and co-workers shows that the formation of secondary sulfate aerosols from SO2 increases in the presence of NOx.

This study explores the cooperative transition of SO2 and NOx into secondary aerosols on the surfaces of carbon-containing particles through heterogeneous reactions. The formation of sulfates from SO2 is promoted by the existence of NOx. Results show that as the particle size increases, the fractional contributions of secondary inorganic ions, such as sulfate and nitrate, also increase (Figure 1). The hygroscopicity of the particles increase and the increased water content can accelerate the gas–liquid–solid reactions of SO2 and NOx, which further increases the hygroscopicity of the particles. These processes form a positive feedback mechanism that enhances the conversion of primary gas pollutants into secondary aerosols. Consequently, it is important to reduce emissions of the precursor gases of PM2.5 to reduce the overall PM2.5 concentrations in the atmosphere. The authors conclude that in central and eastern China, SO2 and NOx should be controlled synchronously to reduce PM2.5 concentrations.

Corresponding author:

LIU Zirui
lzr@dq.cern.ac.cn
See the article:
WANG, Y. S., YAO, L., WANG, L. L., LIU, Z. R., JI, D. S., TANG, G. Q., ZHANG, J. K., HU, B., XIN, J. Y. Mechanism for the formation of the January 2013 heavy haze pollution episode over central and eastern China. SCIENCE CHINA Earth Sciences, 2014, doi: 10.1007/s11430-013-4773-4.

links: http://link.springer.com/article/10.1007%2Fs11430-013-4773-4.

Science China Press Co., Ltd. (SCP) is a scientific journal publishing company of the Chinese Academy of Sciences (CAS). For 60 years, SCP takes its mission to present to the world the best achievements by Chinese scientists on various fields of natural sciences researches.

YAN Bei | EurekAlert!
Further information:
http://www.scichina.org

More articles from Earth Sciences:

nachricht Errant Galileo satellites will be used for research on Einstein’s general theory of relativity
31.08.2015 | Zentrum für angewandte Raumfahrttechnologie und Mikrogravitation (ZARM)

nachricht Time travel into the past of marginal seas: IOW expedition explores Canadian coastal waters
31.08.2015 | Leibniz-Institut für Ostseeforschung Warnemünde

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Increasingly severe disturbances weaken world's temperate forests

Longer, more severe, and hotter droughts and a myriad of other threats, including diseases and more extensive and severe wildfires, are threatening to transform some of the world's temperate forests, a new study published in Science has found. Without informed management, some forests could convert to shrublands or grasslands within the coming decades.

"While we have been trying to manage for resilience of 20th century conditions, we realize now that we must prepare for transformations and attempt to ease...

Im Focus: OU astrophysicist and collaborators find supermassive black holes in quasar nearest Earth

A University of Oklahoma astrophysicist and his Chinese collaborator have found two supermassive black holes in Markarian 231, the nearest quasar to Earth, using observations from NASA's Hubble Space Telescope.

The discovery of two supermassive black holes--one larger one and a second, smaller one--are evidence of a binary black hole and suggests that supermassive...

Im Focus: What would a tsunami in the Mediterranean look like?

A team of European researchers have developed a model to simulate the impact of tsunamis generated by earthquakes and applied it to the Eastern Mediterranean. The results show how tsunami waves could hit and inundate coastal areas in southern Italy and Greece. The study is published today (27 August) in Ocean Science, an open access journal of the European Geosciences Union (EGU).

Though not as frequent as in the Pacific and Indian oceans, tsunamis also occur in the Mediterranean, mainly due to earthquakes generated when the African...

Im Focus: Self-healing landscape: landslides after earthquake

In mountainous regions earthquakes often cause strong landslides, which can be exacerbated by heavy rain. However, after an initial increase, the frequency of these mass wasting events, often enormous and dangerous, declines, in fact independently of meteorological events and aftershocks.

These new findings are presented by a German-Franco-Japanese team of geoscientists in the current issue of the journal Geology, under the lead of the GFZ...

Im Focus: FIC Proteins Send Bacteria Into Hibernation

Bacteria do not cease to amaze us with their survival strategies. A research team from the University of Basel's Biozentrum has now discovered how bacteria enter a sleep mode using a so-called FIC toxin. In the current issue of “Cell Reports”, the scientists describe the mechanism of action and also explain why their discovery provides new insights into the evolution of pathogens.

For many poisons there are antidotes which neutralize their toxic effect. Toxin-antitoxin systems in bacteria work in a similar manner: As long as a cell...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Networking conference in Heidelberg for outstanding mathematicians and computer scientists

20.08.2015 | Event News

Scientists meet in Münster for the world’s largest Chitin und Chitosan Conference

20.08.2015 | Event News

Large agribusiness management strategies

19.08.2015 | Event News

 
Latest News

Production research by Fraunhofer IAO honored with three awards at the ICPR 2015

31.08.2015 | Awards Funding

Single-Crystal Phosphors Suitable for Ultra-Bright, High-Power White Light Sources

31.08.2015 | Materials Sciences

Manchester Team Reveal New, Stable 2D Materials

31.08.2015 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>