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 Sea ice extent sinks to record lows at both poles
23.03.2017 | NASA/Goddard Space Flight Center

nachricht Less radiation in inner Van Allen belt than previously believed
21.03.2017 | DOE/Los Alamos National Laboratory

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

When Air is in Short Supply - Shedding light on plant stress reactions when oxygen runs short

23.03.2017 | Life Sciences

Researchers use light to remotely control curvature of plastics

23.03.2017 | Power and Electrical Engineering

Sea ice extent sinks to record lows at both poles

23.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>