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California is generally reckoned to be a trendsetter - it's not necessarily that things are invented there but California is often an early adopter. Think raves, skateboards, hippies and a whole smorgasbord of drugs. So what's next?

There's a cloud-chasing meet and I want to win. And no. Not the clouds in the sky. So here's the set-up. I want a sub-ohm rechargeable, authentic mech mod so that I that can crank up the power. And a metal rebuildable atomizer. Drip tip, of course, and then a wire coil with a dual silica wick.

I know its old-fashioned but, you know what? I've never liked the eco wool. And steel mesh? I haven't seen one of those for months now. That's for cave men.

Nic level? Three milligrams. And, let's go for organic kosher shazamazam - it's a bit like the grape candy you can get in Korea, if you've ever had that.

Any idea? That's vape talk - the new vocabulary that surrounds e-cigarettes. There's a whole new subculture.

There are hundreds of vape shops in California - more than a thousand some say - and they come in all shapes and sizes. There are chic ones, which look a bit like bars. There are loungey ones where there are sofas for customers to sip a coffee as they vape. And there are arty ones with rap music, grey concrete floors and pictures for sale on exposed brick walls.

Image copyright Getty Images Image caption Some of the flavourings available for use in e-cigarettes

Inside the shops there are vaping magazines, some showing lingerie-clad women puffing away at their e-cigarettes. And there's already a whole industry in accessories: clothing, bags and wooden cases for the juice or e-juice - that's the liquid that you vaporise.

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The scientists say there is not yet enough evidence to be sure what harm smoking e-cigarettes or vaping may do. There are a number of question marks.

First of all, what about the nicotine? A lot of the damage done by cigarettes comes not from the nicotine but from the process of burning tobacco and inhaling the smoke. The latest US surgeon general's report took a look at what harm nicotine itself can do and concluded it is bad for foetuses and bad for adolescents' brain development, but that there's not enough evidence to say whether or not it causes cancer.

Some scientists advise using the precautionary principle and suggest either banning e-cigarettes or maybe changing the tobacco tax into a nicotine tax.

And after all, if large enough numbers get addicted to vaping and then it's discovered that there's a medical problem down the line, what then? Would controls at that point become politically difficult?

There are other issues - are the flavourings and other ingredients safe?

US officials have warned that some of the flavourings being used are safe to eat but dangerous to inhale. Also if the e-cigarettes get too hot, do metal particles get into your lungs? And if set up wrong can they blow up - that has apparently happened - causing serious injury and, in at least one case, death.

Others argue that without strong evidence of harm, there's no case for controls on vaping.

Image copyright AP

But still, in some parts of California, restrictions on vaping indoors and in public spaces are coming in. The state, it seems, is leading the way not only in vaping but also in the control of vaping.

And having spent a few hours in some Los Angeles vape shops, I can say there does seem to be a passive vaping effect - I left the shops with a dry mouth and the feeling, anyway, that some of the nicotine floating around in the air had ended up in my system.

But vaping enthusiasts have few doubts. Their evidence is mostly anecdotal but there are a lot of people saying that vaping has helped them quit smoking.

Take Colin Ring. Tall, fair-haired and clever, he lives in Los Angeles and hopes to study dentistry. A year ago he had a serious medical problem and, after surgery on his stomach, had to quit smoking. So he took to vaping.

"Its all about harm reduction," he says. He now works in a vape shop and says he is steadily reducing the amount of nicotine he inhales and has the final objective of getting to zero, at which point he says he will stop vaping altogether. There is a bit of social vaping, he says, but most see it as a way of transitioning to becoming nicotine free.

In fact, the emerging vaping subculture is quite hostile to the big tobacco companies. There is fear that the cigarette companies see vaping as a threat and will get in on it by making e-cigarettes themselves - in fact that is already happening - or that they will use their lobbying power to regulate vaping out of existence.

But for all that, Colin sees a big future for vaping. 2015 is going to be huge he says. Vaping's here to stay. You might think it's nerdy and there are some vaping snobs who look down on other people who have just started, but you always get that.

"For me," he says, "it's got a New-Age feel. The technology is changing every month. Hey, it's just in its infancy."

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