The EPA says half a million of VW's cars violate the law in the US alone. The company's stock price is plummeting, and VW has already been hit with a lawsuit filed on behalf of car owners.

But what does all of this mean for the environment?

Judging by VW's own recent admission, we're looking at 11 million cars on the road that have the cheating equipment installed. 

In the US, affected VW vehicles are putting out up to 40 times as much nitrogen oxide (NOx) as they are supposed to, according to the EPA. While that is most likely a pretty high estimate, it's still a very big deal.

For one thing, NOx is a nasty pollutant that, in addition to occasionally contributing to a warmer planet, can exacerbate dozens of health conditions, including asthma, bronchitis, and emphysema.