From November 2017 through February 2018, The Real Urban Emissions initiative (TRUE) conducted a project using remote-sensing technology to measure in-use exhaust emissions from vehicles at several sites in Greater London. More than 100,000 samples were collected at nine locations from passenger cars, light commercial vehicles, taxis, buses, trucks, and motorcycles.
The data obtained in this measurement campaign was analysed separately but also in combination with existing data collected over the past decade in Europe. That existing data had formed the basis of the initial TRUE vehicle emissions rating, and the addition of the London data makes it possible to refine and expand the TRUE ratings.
Some highlights of the London data:
- Nitrogen oxide (NOx) emissions from diesel cars in London are, on average per kilometer, 6 times those of petrol cars. NOx emissions from petrol cars have declined, and on average for Euro 5 and Euro 6 vehicles are within 1.35 times the regulatory limits. Average NOx emissions from Euro 5 and 6 diesel cars, however, are approximately 6 times higher than the standards.
- Particulate matter (PM) emissions from passenger cars are low for new diesel and petrol cars. Diesel cars, Euro 5 and newer, come equipped with particulate filters and demonstrate significantly lower PM emissions than older vehicles without filters.
- London's famous black taxi diesel models produce, on average, higher NOx emissions than diesel passenger cars covered by the same emissions standard. NOx emissions from Euro 5 taxis are higher than those from taxis certified to previous Euro standards and are approximately 3 times those of other Euro 5 diesel cars.
- Average NOx emissions from buses in London have declined significantly over the past 5 years. NOx emissions (grams per kilogram of fuel burned) from buses sampled were 65% lower than those from buses sampled in similar studies conducted in 2012 and 2013. A similar comparison for other vehicle types shows that over the same time period average emissions from the diesel passenger car and light commercial vehicle fleet have decreased by 22% and 15%, respectively, while average NOx emissions from the taxi fleet have not improved.