This document discusses challenges with meeting roadside NO2 emission standards and issues with assuming zero-emission vehicles are completely emission free. Some key points made include: 1) Some diesel vehicles still emit over 12 times the legal NOx limit, and vehicle emissions aren't checked annually. 2) Electric vehicles can lead to increased non-exhaust particulate emissions from brake wear and tire wear, and can cause local NO2 exceedances if charging relies on emergency diesel generators. 3) The UK's air quality standards for particulate matter are higher than WHO guidelines, and meeting WHO guidelines by 2030 as pledged may lead to new exceedances being identified.

1. Are zero-emission
vehicles really free of
emissions?
Robert Benney

2. Introduction
 About me;
 Compliance with roadside NO2 standards;
 Challenges facing roadside NO2 compliance;
 Emission Paradox – Zero Emission Vehicles;
 Knock, knock WHO’s there; and
 Summary.

3. Compliance with Roadside NO2 standards

4. Challenges facing Roadside NO2 compliance
 Some Euro VI fail to meet emission standards: 2016 Fiat 500 XL emits over 12
times more NOx than emission standard (0.08 g/km);
 No annual review of vehicles NOx emission rate: MOT currently only checks smoke
number;
 Emission cheat devices;
 Will charging clean air zones deter more polluting vehicles as anticipated; and
 Blind spots in LAQM or PCM methodology.

5. Emissions Paradox – Zero Emission vehicles
 Break and tyre wear and resuspension of road particulates;
 Electric Vehicle Weight Vs Internal Combustion Weight;
 Timmers et al paper shows the evidence for increased non-exhaust emissions and
weight;
 Current peak electricity demand is 60 GW, National Grid forecasts between 6 to 18
additional GW – equivalent to 2 to 6 Hinckley Point Cs; and
 22% of National Grid’s STOR energy from emergency diesel generators.
1 – 1.2
tonnes
1.5
tonnes

6. Knock, Knock, WHO’s there?
 Ambient Air Quality and UK Air Quality Standards Particulates (except
Scotland) higher than World Health Organisation;
 WHO Guideline Values may cause problems; and
 Manchester pledged to meet WHO PM2.5 standard by 2030.

7. Summary
 Compliance with NO2 standards ‘shortest time possible’ will face challenges;
 Eventually there will be compliance with roadside NO2 concentrations;
 Electric Vehicles could cause localised NO2 exceedances associated within
emergency diesel generators;
 Electric vehicles directly emit non-exhaust particulates;
 Adoption of PMx WHO guideline values into statutory limit values will
introduce exceedances; and
 PM likely to become next problem pollutant.

8. Questions?
 Should we as air quality practitioners only start considering WHO particulate
guidelines once adopted into law/UK policy?