DAURE Microscopy

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This page contains electron microscopy images acquired by Esther Coz of CIEMAT/IDAEA-CSIC at RJ Lee Group, Inc.

The images presented above have been acquired with two different high resolution Scanning Electron Microscopes (FEI Sirion400 and Hitachi S5500). Background has been automatically substracted from images to enhance the morphology, but no post processing has been applied on the particles after acquisition. The different relative content of each of the groups (and subgroups) presented below has been quantified and its variations at different times of the day have been analyzed together with the morphological descriptors of each group with a fully automated SEM (PSEM 500). The data is still under review/analysis. Any commentaries, suggestions or corrections (if any mistake is found) are welcome. Please, email esther.coz@ciemat.es.

DAURE participants are allowed to use the pictures for meetings and presentations with proper acknowledgment. Please, contact Esther Coz in case of publishing to check the image has not been already used.


Images from the BCN site


Primary Biogenic Organic Particles

Despite not being an important group in abundance, the microscopy analysis of PM2.5 samples from BCN site revealed a very rich diversity of this particle type. Several families of spores, vegetative and insect detritus and bacteria have been identified with sizes from 300 nm up to 4 µm. Some of them are frequently mixed with other anthropogenic aerosols.

BCN01-16 Spore.jpg Particle BCN-1
Fungi spore
Sampling: 02/25/09, 7- 9 pm
Size = 3.3 µm
Composition: Major components: C, O; Minor components: S, Cl, Ca

Notes:
Hiliferous appendix on the lower right, smooth ornament.

FEI BCN012 1.jpg Particle BCN-2
Non classified
Sampling: 02/28/09, 5.30-7.10 pm
Size = 410 nm
Composition: Major components: C, O; Minor components: S, Cl

Notes:
Morphology with circular aperture and ornament that reminds a fungi spore.

BCN05 15 detritus.jpg Particle BCN-3
Vegetative detritus
Sampling: 02/26/09, 7.40-8.20 pm
Size = 440 nm
Composition: Major components: C, O; Minor components: Al, Si (not always)

Notes:
The morphology reminds a vegetative tissue in which some volatile material was initially entrapped (see the open cut).

FEI BCN01 18.jpg Particles BCN-4 & BCN-5
Fungi spores (possible)
Sampling: 02/25/09, 7-9 pm
Size = 420 nm
Composition: Major components: C, O; Minor components: S, Si, Cl, Na, K

Notes:
Different morphologies of possible fungi spores with similar size and elemental composition. The one on the lower right has golf ball texture and seems to have volatile contain. Both of them are very abundant in the samples and frequently found mixed with soot agglomerates.


Heavy Metal Oxides

Frequently found in the PM2.5 samples collected during traffic peak hours with sizes from 800 nm up to 5 µm. Some of them are frequently mixed with mineral particles. The most abundant are iron oxides (frequently linked to minor contents of titanium and zinc).

BCN01-33 Iron oxide.jpg Particle BCN-6
Iron oxide
Sampling: 02/25/09, 7-9 pm
Size = 1.9 µm
Composition: Major components: Fe2O3; Minor components: Si, S, Ti, Mg, Cl, Na

Notes:
Agglomerate structure and associated minor elements typical from vehicle emissions.

File03 FE-Zn Oxide.jpg Particle BCN-7
Iron-zinc oxide
Sampling: 02/26/09, 11-12 am
Size = 1 µm
Composition: Fe2O4Zn; Minor components: Mn, Cr, Ca, Mg, S, Si, Al

Notes:
Spherical morphology frequently associated to industrial combustion processes.

File07 Iron oxide.jpg Particle BCN-8
Iron oxide
Sampling: 02/25/09, 7-9 pm
Size = 3 µm
Composition: Fe2O3; Minor components: Si, S, Cu, Cl, Mg, Al, Ca

Notes:
Associated minor elements indicate possible anthropogenic origin.


Mineral Particles

FEI BCN013 1.jpg Particle BCN-9
Spherical AluminoSilicate (SAS particle)
Sampling: 02/28/09, 8.45 - 9.25 pm
Size = 800 nm
Composition: SiO2, Al2O3; Minor components: Ca, S, Na, Fe

Notes:
Spherical aluminosilicate related to coal fired power plant emissions. Also denoted as fly-ash.
Frequently found as single particles (not agglomerated) with a wide size range from several nanometers to several micrometers.

BCN01-47 calcite.jpg Particle BCN-10
Calcium carbonate (calcite)
Sampling: 02/25/09, 7-9 pm
Size = 1.6 µm
Composition: CaCO3


BCN01-37-38 quartz.jpg Particle BCN-11
Quartz
Sampling: 02/25/09, 7-9 pm
Size = 1.7 µm
Composition: SiO2

Notes:
Image taken at 2 kV (left) and 15 kV (right) allows to compare how different particles may look if changed any operation value.

BCN01-39 Gypsum.jpg Particle BCN-12
Calcium sulfate (gypsum)
Sampling: 02/25/09, 7-9 pm
Size = 1.1 µm
Composition: CaSO4-2(H2O)

Notes:
Tabular crystal of calcium sulfate(probably gypsum).


Soot-like Agglomerates

Soot-like is the most abundant particle structure for all the samples independently of the day and time of sampling. Larger percentage of "fresh" type (BCN-13) are found on samples associated to traffic peak hours, when the opposite trend (larger abundance of "aged" type, BCN-14) occurs for samples collected during the rest of the sampling times. These types of structures are generally linked to diesel emissions. However, other type of aerosols, such as certain biogenic organic compounds, can be also linked to this type of structures.

FEI BCN04 18 soot.jpg Particle BCN-13
Fresh soot-like agglomerate
Sampling: 02/26/09, 3-4 pm
Size = 290 nm
Composition: Major components: C, O; Minor components: S, Si, Na

Notes:
Chain-like structure of agglomerates generally indicates the aerosol is fresh. Size of the primitive particles ranges from 40-60 nm. The agglomerate is coated with a sulfate (possible organic/sulfate mixture) layer.

FEI BCN06 Soot 5.jpg Particle BCN-14
Aged soot-like agglomerate
Sampling: 02/26/09, 7.30-8 am
Size = 390 nm
Composition: Major components: C, O; Minor components: S, Si, Na

Notes:
Sponge structure indicates aerosol aging. The coating thickness in this type of structues strongly varies with the time of the day due to the condensation of organics on the surface.


Other Carbonaceous Particles

Examples of some other carbonaceous particles (probably organic aerosols) found in the samples are presented next.

BCN01-14 organic.jpg Particle BCN-15
Other carbonaceous particles
Size = 350 nm
Composition: Major components: C, O

Notes:

FEI BCN03 1 copia.jpg Particle BCN-16
Other carbonaceous particles
Size = 530 nm
Composition: Major components: C, O

Notes:


Sulfates

BCN03 18 Sulfate.jpg Particle BCN-17
Sulfate
Size = 510 nm
Composition: Major components: S, O

Notes:
Probably ammonium sulfate or bisulfate

BCN02 1 Sulfate.jpg Particle BCN-18
Sulfate
Size = 215 nm (360 nm, sulfate + soot-like)
Composition: Major components: S, O

Notes:
Bubble shaped ammonium sulfate linked to a soot-like structrure typical from diesel emissions.

Images from the MSY site

Upcoming...


Acknowledgements

The electron microscopy images contained in this page have been acquired by Esther Coz of CIEMAT/IDAEA-CSIC at RJ Lee Group, Inc.

The work has been partially funded by the following projects of the Spanish Ministry of Science and Innovation:
- GRACCIE Project, CSD2007:0067
- Acción Complementaria CGL2008- 02817-E/CLI
- Project CGL2007-64117/CLI