wxman
Veteran Member
The "hair on fire" presentation in that video after ~22:00 minutes regarding the air quality in Europe is overly dramatic, IMHO. The ambient NO2 levels in 2016 were above the European ambient air quality standards in only 7% of the monitoring locations. Even then, Europe decided to adopt the WHO air quality guidance (AQG) for NO2, but *NOT* for any of the other criteria pollutants. The ambient NO2 AAQS and WHO AQG are set at 40 µg/m3, which is more than twice as strict as the U.S. NAAQS (53 ppb or ~103 µg/m3). No European monitor would have exceed the U.S. NO2 NAAQS, according to that report.If you look back at the history of emissions in diesel engines in Europe vs the united states, it's fairly clear why they never gained major acceptance in the USA. They (diesel engines) were often given preferable emission laws that were more lax then what gas engines had to meet. It wasn't till the late 90's (ish) that the eu started getting serious about emissions in diesels. They never really had a large market share in the USA because our standards were a lot tighter, and the perception of dirty, noisy diesels was never really put to rest.
Actually a fairly good video on the topic.
Regarding the assertion that "most" PM comes from diesel engines, a 2015 study in London (Bohnenstengel et al., “Meteorology, Air Quality, and Health in London.” Bulletin of the American Meteorological Society, May 2015) concludes that most of the black carbon (BC) captured at monitoring sites comes from residential wood burning. Even then, the average BC concentration at the most urban location tested averaged 1.9 µg m−3 out of total PM10 of 18.59 µg m−3, only about 10%. PM from diesel engines is about 75% BC according to an EPA study.
In France, two-stroke scooters and wood burning were the biggest contributors to ambient PM2.5.