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| Titel |
Black Carbon Particle Number Distribution Measurements during the ATHENS-2013 Winter Campaign |
| VerfasserIn |
Georgios Gkatzelis, Dimitris Papanastasiou, Kalliopi Florou, Christos Kaltsonoudis, Eyaggelos Louvaris, Spiridon Bezentakos, Georgios Biskos, Spuros Pandis |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250097298
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| Publikation (Nr.) |
 EGU/EGU2014-12861.pdf |
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| Zusammenfassung |
| Black Carbon (BC) particles emitted by anthropogenic sources play an important role both in
climate change and in air quality degradation. Open burning in forests and savannas,
combustion of diesel and solid fuels for cooking and heating in homes represent
the majority of BC emissions. Earlier work has focused on the BC atmospheric
direct radiative forcing that is mostly related to its mass concentration and optical
properties of the corresponding particles. A variety of measurement techniques are
used to measure the mass concentration of BC by taking advantage of its optical or
physical properties. Moreover, the carbonaceous particles containing BC are also
important for the indirect forcing of climate. This effect is mostly related to the number
concentration of BC particles. The number distribution of BC particles especially
below 100 nm is quite uncertain due to limitations of the existing measurement
techniques.
In this work we employed a thermodenuder-based method as an approach for the
measurement of the BC number distribution. More specifically, we combined a
thermodenuder (TD) operating at temperatures up to 300 °C, with a Scanning
Mobility Particle Sizer (SMPS) and a High Resolution Time of Flight Aerosol
Mass Spectrometer (HR-ToF AMS). Aerosol size and composition measurements
were carried out both at ambient and at elevated TD temperatures in Athens field
campaign during January and February of 2013. In parallel, a Multi-Angle Absorption
Photometer (MAAP) provided information about the BC mass concentration while
a Hygroscopic Tandem Differential Mobility Analyzer (HTDMA) measured the
mixing state and the hygroscopicity of the particles as a function of their size. These
measurements were then combined to estimate the number concentration of BC
particles.
Our analysis focused on different periods during the study. During some of
them one source dominated the carbonaceous aerosol concentration. Such periods
included rush hour traffic, nighttime wood burning, clean air transported from other
areas, mixed sources, etc. The number fraction remaining after heating at 300 °C
for approximately 15 s during wood burning events was 80-90%, suggesting that
practically all particles contained nonvolatile material. Combining the SMPS, MAAP,
AMS, and HTDMA measurements we show that most of the sampled material was
BC. On the contrary, during rush hour traffic the number fraction remaining was
only 50-60% suggesting that more than half of the particles did not contain BC. |
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