Hello everyone,
as part of a university study project, I am currently analyzing the dataset
“[2013] Emissions de polluants, CO₂ et caractéristiques des véhicules commercialisés en France” from data.gouv.fr.
(Link: https://www.data.gouv.fr/datasets/emissions-de-co2-et-de-polluants-des-vehicules-commercialises-en-france/?resource_id=6ff09b59-84ca-4346-a8d1-3587ed94da15)
During the analysis, several technical uncertainties have arisen for which I could not find clear documentation. I would greatly appreciate any clarification on the following points:
1. Variable „typ_boite_nb_rapp“
“type of gearbox and number of gears”
One of the modalities has the value “V0”.
Unfortunately, I could not find any explanation in the dataset or the accompanying documentation as to what this value represents.
• Does it refer to a specific type of transmission (e.g. continuously variable, automated, etc.)?
• Or should it be interpreted as a placeholder or missing/unknown value?
2. Variable „ptcl“
“particle test result”
The unit of measurement is given as g/km.
However, particle emissions are usually reported as particle number per volume (e.g. or particles/m3).
• Is this value the result of a conversion (e.g. particle mass per kilometer)?
• Or is a different measurement methodology being applied in this dataset?
Olso there are a large number of zero values. Any suggestions on this topic?
3. Variables „hc“, „nox“, and „hcnox“
“test results”
Several questions arise here:
• How exactly is hcnox measured?
• Is „hcnox“.measured directly, or is it calculated from other measured values?
In addition, the variable „hc“,and „hcnox“ shows a very large number of missing values:
• Is there a known regulatory or methodological reason for this?
• For example, is „hc“ only reported for certain vehicle or fuel types, or was it not required to be reported separately in some emission standards where only „hcnox“ was regulated?
If anyone has experience with this dataset, the underlying EU type-approval and emissions testing procedures, or relevant technical documentation, I would be very grateful for any insights or references.
Thank you in advance and best regards!