Umh. Water vapor doesn't cause cancer or dying. Or am I missing something?

mzurer - rest assured, the D.M.R.D. will not allow this vehicle to be sold in the USA.

Humidity, mzurer. A big city would be saturated with water vapour. It'd be awful.

excellent point. Water vapor is in fact a greenhouse gas. It is in fact the most abundant greenhouse gas in the atmosphere. Most of it is of natural causes, some of it is anthropogenic.

Hydrogen car technology (from the little I've read) has not been scrutinized at this point to assess how much localized emissions of water vapor could affect climate. This is because CO2 and CH4 (the main problems) unlike water vapor are well mixed in the atmosphere. Whereas, water vapor takes part in local hydrological cycles, which are very fast, eg clouds, rain etc which *may* not affect global climate.

Uh.... NO.

water vapor is harmless... it will have no negative impacts at all.

And let's not forget - water conducts electricity. Think of the potential damage it could cause, not just to a car and its driver, but to the local infrastructure.

They are DANGEROUS.

Or something.

Where's my horse??

The nice thing about water vapor is that it easily condenses out of the air, unlike C02 or methane. Any extra that was contributed by H2 cars would just generate a little extra rain, dewpoints being what they are...

Ah well. As someone who has an allergic reaction to petrol (and diesel and propane) exhaust fumes (and other chemicals--WOW, does Windex do the trick fast) that causes my windpipe to swell shut to the size of a cocktail straw, I'd be much happier breathing water mist. Especially, ya know, when biking and breathing hard to begin with.

Welcome, carldec.

I suppose the bigger cities would never notice the difference. LA would still be beneath a cloud. It'd just be grey, not brown.