Ethical Performance
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Online calculator helps drivers through emissions haze

November 2015

Following the VW Group emissions scandal and renewed focus on air quality, UK website Next Green Car (NGC), has updated its ratings to account for known discrepancies between official and real-world CO2 and NOx emissions.

The updated methodology also powers a new Car Emissions Calculator which enables car buyers to calculate total carbon dioxide (CO2), nitrogen oxides (NOx) and particulate (PM10) emissions for any new or used UK car or van. Official or real-world driving emissions can be calculated according to distance travelled and driving style.

To more accurately estimate real-world emissions, a series of correction factors have been applied to the official test figures. Real-world CO2 emissions are estimated by applying ‘mpg factors’ published by the ICCT1 for petrol and diesel cars. These factors vary by year from 1.07 in 2000 to 1.39 in 2015. This means, for example, that tailpipe CO2 emissions for a petrol or diesel car registered in 2015 are typically 39% higher than the official test figures suggest.

For tailpipe NOx emissions, real-world emissions are estimated by applying ‘conformity factors’ to official figures. These factors, which vary by Euro standard: Euro 2 (1.0), Euro 3 (1.5), Euro 4 (2.4), Euro 5 (3.6), Euro 6 (5.5 est.), are published by COPERT 42 and the ICCT for diesel cars. This means for example that the NOx emissions for a Euro 6 diesel car are typically 5.5 times higher than the official test figures (assuming ‘defeat devices’ not used).

Incorporating the new correction factors, the NGC Rating says it more accurately represents the environmental impact of different fuel and vehicle types.

To help car owners better understand the most important emissions, the results presented by the Emissions Calculator include CO2, NOx and PM10 for selected vehicles.

The results are broken down into direct emissions (tailpipe) and indirect emissions which are generated during fuel and vehicle production.

Car buyers can then calculate the level of emissions for a given journey distance and driving style.

More information click here.  


UK & NI Ireland | carbon


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