alt Hacker NewsDoesn't it really depend? Like I recall Oxford Street in London at one point was notoriously bad because it was a bottleneck for a lot of slow moving traffic so that one length of road was especially bad. 10x bad I don't know... But it's not hard to imagine some of the quieter roads filtering off like Berwick St or Dean St would be considerably better
Slow moving traffic at one intersection and free flowing traffic at another could easily account for a 10x ratio of particulate pollution, especially in European capitals where diesels are prevalent.
But a 10x ratio on the same road is also plausible if the Google car is following a large truck on one pass and then driving by itself on the second.