Team car support?
 

When there is a breakaway and the team car moves ahead of the peleton to support the rider(s) in the break, who supports the rest of the team members left behind with the peleton? Are there two team cars or do they get support from a neutral support car? Just curious.

Hey, I don't mean to thread-jack, but I was also wondering about the support vehicles. Do the riders get annoyed by the exhaust fumes at all? Do the support cars run on alternative energy sources? Personally, I'm not bothered much by exhaust, but I could imagine that a competing athlete might be.

Yes. each team has at least two cars. Two are allowed in the convoy, the others go out to do shopping, drive ahead to the hotel etc etc

Yes and no.
Yes the fumes can be quite bad (a lot of team cars are diesel as it the fuel of choice in Europe) but the cars are also a great help to riders returning to the peloton, so you can't complain about shocking fumes from cars one day then slot in behind the same car fior a draft the next.

Besides which it is illegal for riders to draft behind cars or motos, though it is overlooked for a couple of seconds at a time as a rider is trying to make his way back up to the peloton after a wheel change, natural break, crash, etc. So they shouldn't be spending much time breathing fumes.

Hey, this is France, they don't need to worry about fumes, their vehicles run on whine...I mean wine. :)

In addition to the team vehicles there are also neutral service vehicles for things like wheels, water, etc.

press motorbikes
radio and TV motorbikes
commissaires motorbikes bikes and cars
doctor's car
voiture balai

There's a diagram online that shows the layout of the whole tour procession.