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| Titel |
On-line measurements of particle-bound reactive oxygen species (ROS) in Beijing wintertime air |
| VerfasserIn |
Sarah Steimer, Francis Wragg, Markus Kalberer |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250152421
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| Publikation (Nr.) |
 EGU/EGU2017-17255.pdf |
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| Zusammenfassung |
| Reactive oxygen species (ROS), present in particles or generated by particle components
upon deposition of particles in the human lung, are widely thought to be one of the main
contributors to particle-related toxicity. However, there is so far only relatively little data
available on their concentrations in ambient air, which makes it difficult to gauge their impact
on air quality. Recent studies have shown that a large fraction of particle-bound
ROS in secondary organic aerosol is relatively short-lived, with lifetimes of several
minutes. Traditional off-line sampling with high-volume samplers is therefore likely to
severely underestimate ROS concentrations, showing the need for using on-line
instrumentation.
We have recently developed a compact on-line instrument for the measurement of
particle-bound ROS (OPROSI). To measure ROS concentrations, particles are continuously
extracted and the extract is reacted with 2’7’-dichlorofluorescein (DCFH) in presence of
horseradish peroxidase (HRP). This leads to formation of a fluorescent dye, which is detected
spectroscopically. The instrument allows for up to 16 h of continuous measurement with a
time resolution of ≤12 min and a limit of detection of 3.85 nmol [H2O2] equivalent per m3
air.
For this study, we have used the OPROSI to continuously measure the concentration of
particle-bound ROS in Beijing wintertime air during the first half of the Air Pollution and
Human Health in a Developing Megacity (APHH-Beijing) campaign in November and
December 2016. Measured ROS data are compared with other air pollution parameters such
as total particulate mass, ozone and NOx as well as with meteorological measurements such
as temperature and humidity. |
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