FOI request detail

Non-ULEZ Compliant Cars

Request ID: FOI-0172-2324
Date published: 17 May 2023

You asked

Follow-on from FOI-3070-2223: You state: « The ULEZ is designed to reduce emissions of oxides of nitrogen (NOx) which contributes to concentrations of nitrogen dioxide which is damaging to human health ». As such, please could you reply to my amended question 3: 3. What is the percentage of oxides of nitrogen (NOx) produced by non-ULEZ compliant cars as a percentage of all cars (non-ULEZ compliant and ULEZ compliant) within London (inner and outer) ? You must have this data since the expanded ULEZ is supposed to reduce the 4,000 annual deaths from concentrations of nitrogen dioxide. And this information can only be available if you have calculated the total mileage covered by non-ULEZ compliant cars (and taking into consideration their ULEZ Euro rating) in comparison to the total mileage covered by all cars in London (non-ULEZ compliant and ULEZ compliant). Indeed, as I mentioned previously, younger and richer drivers would drive newer cars and probably generate more oxides of nitrogen, than older and poorer drivers who drive older and non-ULEZ compliant cars. But those creating the most pollution are not being hit by ULEZ - just the old and poor.

We answered

Our Ref:         FOI-0172-2324

Thank you for your request received on 17 April 2023 asking for further information about non-Ultra-low Emission Zone (ULEZ) compliant cars.

Your request has been considered in accordance with the requirements of the Environmental Information Regulations and our information access policy. You asked:

What is the percentage of oxides of nitrogen (NOx) produced by non-ULEZ compliant cars as a percentage of all cars (non-ULEZ compliant and ULEZ compliant) within London (inner and outer)?
We do not hold the information in the format you have requested because our emissions modelling tools combine all of the emissions from all vehicle types and euro standards and then compares the total emissions both with and without the ULEZ expansion.  Within the processing we do take account of hundreds of different emissions factors across vehicle types, fuel types and Euro standards.
Looking at a comparison of individual euro standards, we know from the emissions factors (in this case for a speed of 20kph) for each of the euro standards for average fleet-weighted vehicles that a Euro 4 petrol (compliant) car is estimated to produce 0.1 g/km NOx compared to a Euro 4 diesel (non-compliant) car which we estimate emits approximately 0.76g/km. This means on a like for like comparison the non-compliant Euro 4 diesel car is emitting seven and a half times more NOx than the compliant Euro 4 petrol car.

If this is not the information you are looking for please do not hesitate to contact me.

Please see the attached information sheet for details of your right to appeal.

Yours sincerely

Gemma Jacob
Senior FOI Case Officer
FOI Case Management Team
General Counsel
Transport for London

[email protected]

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