Licensees are struggling to meet the industry's Public Places Charter on smoking because of mixed messages from ventilation and air-cleaner manufacturers.
Campaign group AIR (Atmosphere Improves Results) has slammed firms for giving out confusing messages after they received complaints from licensees and pub groups.
Licensees have claimed that whereas some representatives have said that fans do not need to be used with their air-cleaning systems, other manufacturers insist on them.
AIR says this confusion is slowing the trade's progress in complying with the charter, which recommends the use of signage, with no-smoking areas and ventilation where possible.
In a letter to AIR, Dawn Hopkins, who runs the Ketts Tavern in Norwich, wrote: "For the last 18 months I have been trying to improve our pub's air quality and I am very confused.
"We have read the charter and feel we have a good understanding of what is required with regards to ventilation, however we get told a different story from the manufacturers."
Tony Payne, chief executive of the Federation of Licensed Victuallers Associations, said: "Licensees are easy prey because they do not understand what technology is required.
"I advise all members to get everything in writing and speak to AIR."
Jeremy Cockroft, a spokesman for Honeywell which provides air-cleaning equipment, said: "I am aware of this issue, but I would advise publicans to make sure they are dealing with a reputable supplier by getting advice from the Air Cleaner Manufacturers' Association (ACMA) or AIR."
The Department of Health has confirmed it will be assessing the effectiveness of the charter at the end of this year.
The government wants 50 per cent of the UK's pubs to be compliant by the end of 2002, with 35 per cent of those demonstrating a good standard of ventilation.
A guide to clearing smoke from your pub is available from AIR by calling 020 7482 0620 or visiting www.airinitiative.com.