Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Characterization of winter organic aerosols in Beijing, China

05.03.2012
Because submicron particulates (PM1) exhibit lengthy atmospheric residence time and are capable of deep pulmonary ingestion, the environmental and health impacts of PM1 are very significant.

Organic aerosol is a large and important fraction of PM1 and has great impact on human health, especially because of some of the compounds have proved to be mutagens or carcinogens. Along with fast economical growth, the air quality in Beijing has suffered severe deterioration, with PM being one of the top pollutants.

Organic matter is the most abundant fraction in fine particles in Beijing, accounting for 30-50% of the total mass, indicating its key role in air pollution control. Because the chemical compositions and sources of OA are complex (they can be classified as either primary OA (POA), from direct emissions, or secondary OA (SOA), from the oxidation of gas-phase precursors), the related studies on their chemical and physical characteristics have become difficult and a recent focus point. High time-resolution online measurements are needed to gain insight into aerosol chemical characteristics, sources and processes.

Professor Wang Yuesi and Dr. Liu Quan from State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences performed the online observation of chemical compositions and size distributions of OA with a HR-ToF-AMS to reveal the variation regularity of organic aerosols in Bejing winter. Meanwhile, based on the data of the mass spectra of organic compounds, major sources of OA were resolved by positive matrix factorisation (PMF). Their work, entitled "In situ measurement of PM1 organic aerosol in Beijing winter using a high-resolution aerosol Mass Spectrometer", was published in Chinese Science Bulletin, 2012, Vol 57(7).

The mean OA mass concentration was 20.9±25.3 ìg/m3 during this campaign, varying between 1.9 and 284.6 ìg/m3. The average mass-based size distributions of OA present a prominent accumulation mode peaking at approximately 450 nm. During this study, the average H/C, O/C and N/C (molar ratio) were 1.70, 0.17, and 0.005, respectively, corresponding to an OM/OC ratio (mass ratio of organic matter to organic carbon) of 1.37. The diurnal pattern of O/C was consistent with that of OM/OC and displayed a typical photochemical characteristic.

Positive Matrix Factorisation (PMF) analysis of the organic mass spectral dataset differentiated the OA into three components (Figure 1): hydrocarbon-like (HOA), cooking-related (COA), and oxygenated (OOA) organic aerosols, which, on average, accounted for 26.9%, 49.7% and 23.4%, respectively. The sum of HOA and COA could be regarded as POA, and the OOA corresponded to aged SOA. The POA is a dominant component of OA in Beijing winter, with a large percentage of 76.6%. The large contribution of COA in the POA mass indicates its key role in PM1 pollution control in Beijing.

See the article: Liu Quan, Sun Yang, Hu Bo et al. In situ measurement of PM1 organic aerosol in Beijing winter using a high-resolution aerosol Mass Spectrometer. Chinese Science Bulletin, 2012, 57 (7): 819-826.

Liu Quan | EurekAlert!
Further information:
http://zh.scichina.com/english/

More articles from Earth Sciences:

nachricht Typhoon changed earthquake patterns
03.07.2020 | GFZ GeoForschungsZentrum Potsdam, Helmholtz Centre

nachricht Groundwater protection on Spiekeroog Island - first installation of a salt water monitoring system
01.07.2020 | Leibniz-Institut für Angewandte Geophysik (LIAG)

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Electrons in the fast lane

Solar cells based on perovskite compounds could soon make electricity generation from sunlight even more efficient and cheaper. The laboratory efficiency of these perovskite solar cells already exceeds that of the well-known silicon solar cells. An international team led by Stefan Weber from the Max Planck Institute for Polymer Research (MPI-P) in Mainz has found microscopic structures in perovskite crystals that can guide the charge transport in the solar cell. Clever alignment of these "electron highways" could make perovskite solar cells even more powerful.

Solar cells convert sunlight into electricity. During this process, the electrons of the material inside the cell absorb the energy of the light....

Im Focus: The lightest electromagnetic shielding material in the world

Empa researchers have succeeded in applying aerogels to microelectronics: Aerogels based on cellulose nanofibers can effectively shield electromagnetic radiation over a wide frequency range – and they are unrivalled in terms of weight.

Electric motors and electronic devices generate electromagnetic fields that sometimes have to be shielded in order not to affect neighboring electronic...

Im Focus: Gentle wall contact – the right scenario for a fusion power plant

Quasi-continuous power exhaust developed as a wall-friendly method on ASDEX Upgrade

A promising operating mode for the plasma of a future power plant has been developed at the ASDEX Upgrade fusion device at Max Planck Institute for Plasma...

Im Focus: ILA Goes Digital – Automation & Production Technology for Adaptable Aircraft Production

Live event – July 1, 2020 - 11:00 to 11:45 (CET)
"Automation in Aerospace Industry @ Fraunhofer IFAM"

The Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM l Stade is presenting its forward-looking R&D portfolio for the first time at...

Im Focus: AI monitoring of laser welding processes - X-ray vision and eavesdropping ensure quality

With an X-ray experiment at the European Synchrotron ESRF in Grenoble (France), Empa researchers were able to demonstrate how well their real-time acoustic monitoring of laser weld seams works. With almost 90 percent reliability, they detected the formation of unwanted pores that impair the quality of weld seams. Thanks to a special evaluation method based on artificial intelligence (AI), the detection process is completed in just 70 milliseconds.

Laser welding is a process suitable for joining metals and thermoplastics. It has become particularly well established in highly automated production, for...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International conference QuApps shows status quo of quantum technology

02.07.2020 | Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

 
Latest News

Moss protein corrects genetic defects of other plants

03.07.2020 | Life Sciences

Typhoon changed earthquake patterns

03.07.2020 | Earth Sciences

New candidate for raw material synthesis through gene transfer

03.07.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>