Regarding the human tests, as scandalous at it sounds on first glance, the SWR & ARD (government funded news channels similar to the BBC) also reported that it apparently isn't unusual to do this kind of human testing. The subjects were exposed to one specific kind of gas, and the dose, according to their correspondent, was less than what someone living at a busy street consumes regularly.
He mentioned that even Greenpeace "knows of these studies", referring to them in one of their papers.., whatever that means exactly.. He also states that the scientists were openly communicating that they were funded by the car manufacturers.
https://www.swr.de/swraktuell/bw/neben-affen-auch-menschenve... (google translate should do a good job if you don't understand German..)
https://media.ccc.de/v/32c3-7331-the_exhaust_emissions_scand...
http://www.telegraph.co.uk/news/2018/01/31/suppressed-rigged...
https://news.nationalgeographic.com/2018/02/wildlife-watch-l...
https://www.theguardian.com/business/2018/jan/30/vw-suspends...
http://www.bbc.com/news/business-42876336
>The exhaust fume tests were carried out by EUGT, a now disbanded body that had been funded by VW as well as rivals Daimler, which owns Mercedes Benz, and BMW.
>Last week the New York Times reported that EUGT had exposed 10 monkeys to fumes - in an air-tight chamber - from several cars, including a diesel VW Beetle, at a lab in Albuquerque.
>In his first public comments on the test, Mr Mueller said: "The methods used by EUGT in the United States were wrong, they were unethical and repulsive. I am sorry that Volkswagen was involved in the matter as one of the sponsors of EUGT."
>Germany's Stuttgarter Zeitung and SWR radio reported that 19 men and six women had inhaled diesel fumes in another EUGT experiment.
VW admits the "optics" of gassing monkeys and humans with diesel exhaust doesn't look quite as good as the "optics" of Hitler delightfully grinning and endorsing their product:
http://www.bbc.com/news/business-34358783