Used vehicles
The Foreign Registration Certificate (FRC), which is a mandatory document for all used vehicles, may contain a NOx emissions figure.
United Kingdom (UK) imports may have the NOx figure on the FRC if the document was issued prior to April 2019. This is usually displayed in box V3 of the V5, the UK registration certificate.
If not present on the FRC, customers are advised to obtain the CoC for the vehicle. This can be obtained by contacting a main dealer, or the manufacturer, directly.
Revenue will also accept official written confirmation from the manufacturer, or an appropriate statutory authority, of the NOx emissions. These will be considered on a case by case basis, depending on the documentation presented.
A NOx figure for Japanese imports can be obtained from the Japanese Ministry of Land, Infrastructure, Transport and Tourism.
If a NOx figure cannot be provided for a vehicle, then a flat charge will apply. Further information can be found in
Nox Charge.
This page explains the cost of the nitrogen oxide charge for vehicles
www.revenue.ie
https://www.mlit.go.jp/en/jidosha/index.html (But I don't know where to get it from there
)