If there's one thing that will be missed about smoky pubs it's that the tobacco masked all kinds of unpleasant smells.
Licensees in Scotland have been quick to complain that it's now the natural biological processes of their customers that are polluting the atmosphere - all those hot sweaty bodies pressed together in an enclosed space can produce quite a whiff, not to mention the occasional eructation of bottom wind.
Even more refined establishments can suffer from unwanted odours. As food raises its profile in the pub so smells waft from the kitchen, from from the pungence of a vindaloo to the reek of a deep fat fryer.
So what is the solution? Domestic air fresheners are probably not up to the job, and may be masking the unpleasant smells with an aroma that is equally unwanted. Your cask ale aficianados will not take too kindly to mountain pine clashing with the delicate goldings hops of their prized pints.
And believe it or not the European Community, gawd bless 'em, are a bit worried about the pollutants in air fresheners (though if you have candles in your pub they could be more of a problem).
The other alternative is an air cleaner - not to be confused with the air cleaners many pubs still have attached to their ceilings from past attempts to clear smoke from the atmosphere.
These used a fan to suck air past electrically-charged plates which attracted the airborne smoke particles - strictly known as particulates by scientists - and blew clean air out the back.
The plates had to be cleaned on a regular basis, of course - one more unwanted chore for the publican, even if they could be bothered to switch the machines on in the first place.
Science has moved on though, as it usually does, and the new air cleaning machines that are starting to appear in pubs are based on ionising technology.
To a large extent the pub industry jury is still out on these machines. But they seem to be well tested in other sectors and have begun to appear in pubs.
Hygiene Technologies imports American ionisers into the UK and is now targeting the licensed trade after having achieved some success in residential care homes.
"The US is obsessed with air and water quality," says director Mark Robinson. "The technology is used to clean the air in the space shuttle. Ions latch onto and destroy anything organic. They get right into the structure of the bacteria that carry malodours.
"We have tested the equipment in a big group of residential care homes in this country and it can clean a whole room in 10 to 12 minutes."
Without going into unsavoury details, residential care homes present a much bigger challenge than the smelliest pubs.
Mark also says that his ionisers will deal with the other problem pubs face in the early days of a smoking ban - the stale odours that will stick around in the pub and continue to make it smell smoky.
"They don't just take the smell out of the air," he says. "They get into fabric, curtains, furniture."
Hygiene Technologies is working with major pubcos including Spirit, Greene King and Laurel and its machines are already installed in English pubs that have been refurbished in advance of the smoking ban.
For an average pub the system will probably come in at under £2,000 and cover the toilets too.
One thing you need to bear in mind with ionisers, though, is that the process that's so efficient at breaking down bacteria also produces ozone which, in high enough concentrations, can be a health and safety risk.
So before splashing out on these machines make absolutely sure that they won't produce a dangerously high concentration of ozone - obviously the size of the room you are treating as well as the power of the equipment comes into play.
Again, there is some debate over what this might be, but you should be all right with anything around 0.05ppm or less.
According to Mark, the Hygiene Technologies machine most suitable for pubs, the Eagle 5000, has a strictly limited output and produces no more ozone than you might find outdoors some days.
The company also makes a 'blaster' for those care home jobs and you have to stand outside the room while it's on. Unless you've got some real problems you won't need a blaster in a pub though.
Hygiene Technologies has also devised two new products for the pubs market - a ducted system for bars that think the Eagle, which looks a bit like an old-fashioned hi-fi speaker, would muck up their sophisticated design concept and a small ioniser for toilets.
Toilets are, of course, an obvious use for ionisers, with or without a smoking ban. Aerstream Technology has made its name in washrooms and has already sold 80,000 of its Cleanaer units for use in toilets around the UK.
This is a slightly different technology, though. Cleanaer is a liquid ioniser that charges the moisture in the air and so doesn't produce ozone.
Unlike conventional ionisers it doesn't have a fan, either, and consequently, at about the size of a baby's arm, it is a much smaller, cheaper - and arguably more attractive - piece of kit.
It was invented by electrostatics boffin Alastair Pirrie. "The charged droplets grab particulates, and because the droplets are massive in comparison they drop them to the floor and you can simply hoover them up."
Aerstream Technology is big on the positive health benefits of its machine. It is also targeting the domestic market, among asthma and allergy sufferers, and is endorsed by the British Allergy Foundation.
For the last few months the system has been on test in one pub, the Westminster Arms in London, where it has been effective in dealing with tobacco smoke.
Because it has no fan, though, Cleanaer needs a good circulation of air to get the ionised water droplets around the room and it has a shorter range. The Westminster Arms, which is an averaged-sized one-bar pub, has five Cleanaers to do the job.
At less than £30 apiece, plus around £7 for replacement cartridges which last about two months, they are potentially an affordable option, though.
And, if you like, they can be subtly scented.
"Cleanaer can help eliminate the odours you don't want and replace them with any smell you want - freshly baked bread, cappuccino, hops, for example," adds Alastair.
For more information...
www.hygienetechnologies.co.uk
www.cleanaer.com