Diesel cars emit more air pollution on hot days, study says
Source: The Guardian
Diesel cars emit more air pollution on hot days, study says
Emissions rose 20-30% in Paris when temperatures topped 30C, raising urgent questions as the climate gets hotter
Kim Willsher
Tue 10 Sep 2019 12.35 BST
Last modified on Tue 10 Sep 2019 17.45 BST
Emissions from diesel cars – even newer and supposedly cleaner models – increase on hot days, a new study has found, raising questions over how cities suffering from air pollution can deal with urban heat islands and the climate crisis.
Research in Paris by The Real Urban Emissions (True) initiative found that diesel car emissions of nitrogen oxides (NOx) rose by 20% to 30% when temperatures topped 30C – a common event this summer.
Emissions from a range of vehicles were found to be many times higher than those declared by manufacturers in laboratory tests, confirming earlier findings following the 2015 Dieselgate scandal, in which Volkswagen cars were found to emit 40 times more NOx on the road than during laboratory tests.
Certain pollutants from motorcycles – often considered a cleaner alternative to four-wheeled vehicles – were also found to “greatly exceed” averages for both petrol and diesel cars.
Launching its latest report, True said it used hi-tech remote-sensing equipment to measure emissions from more than 180,000 vehicles being driven on roads in the French capital during three weeks in summer 2018.
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Read more: https://www.theguardian.com/cities/2019/sep/10/diesel-cars-emit-more-air-pollution-on-hot-days-study-says