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| Titel |
Vehicle Real Driving Emissions of Nitrogen Oxides in an Urban Area from a large Vehicle Fleet |
| VerfasserIn |
Denis Pöhler, Martin Horbanski, Tobias Oesterle, Tim Adler, Miriam Reh, Lukas Tirpitz, Florian Kanatschnig, Joahnnes Lampel, Ulrich Platt |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250129911
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| Publikation (Nr.) |
 EGU/EGU2016-10084.pdf |
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| Zusammenfassung |
| Nitrogen Oxide (NOx=NO +NO2) emissions by road vehicles are the major contributor for
poor air quality in urban areas. High NOx concentrations, and especially NO2,
are typically the most problematic pollution in cities. However, emissions vary
significantly depending on the type of vehicle, its engine, the age, condition of the
vehicle, driving properties, modifications and many more. Even if official NOx
emission data of the manufacturer exist, they are only valid for new vehicles and the
current vehicle emission scandal shows clearly that these data are often wrong.
Thus, real driving emissions (RDE) of the current vehicle fleet is required. With
such data the contribution of individual vehicles to the NO2 and NOx levels in
urban areas can be estimated. Significant reduction of NOx concentrations can be
achieved by identifying the strong emitting vehicles and excluding, replace or modify
them.
We developed a precise and fast ICAD (Iterative CAvity DOAS) NO2 instrument
which can measure the concentration within the emission plume of vehicles under
real driving conditions. The sampling was performed with an inlet at the front of a
car which was following the investigated vehicles. The instrument measure NO2
and additionally CO2 with a time resolution of 2 seconds. With the observed NO2
values already strong emitters can easily be identified. With the use of known CO2
emissions, more reliable emissions for NO2 can be calculated for each vehicle.
Currently the system is expanded with a NOx channel to derive the total nitrogen oxide
emissions.
The system was successfully applied in several studies over the last two years to
investigate NO2 RDE. More than thousand vehicles were investigated. We observed that
several vehicles from various brands show much higher emissions than allowed (more than a
factor of 5). Highest emissions correlate for trucks and busses typically to older vehicles,
what is not the case for cars. A large variability between different cars was found which could
often make up a factor of 10 or more. Often new Diesel cars are one of the strongest emitters,
which agree well with other findings. However, older busses and trucks feature
regularly the highest emissions, but also here strong variability between different
vehicle types with different exhaust treatment and modification is observed. This
is especially a problem with busses from the public transport which significantly
contribute to urban air pollution. Identifying first the strongest emitting busses,
which should be replaced first, can help to faster improve urban air quality. New
busses and trucks, beside from few exceptions, show surprisingly relatively low
emissions. The exceptions indicate potentially broken NOx exhaust treatment. All
these findings show that regular RDE are necessary for the whole vehicle fleet to
identify strongest NOx emitters and develop strategies to reduce their emissions. They
also allow to provide more accurate model calculations on total emissions in urban
areas. |
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