HAVE you been unwell this summer? Suffered headaches, hay fever, asthma, sinus, malaise, a lowered resistance to infections? According to Dr Lilian Vrijmoed, it is no wonder at all if you, like most of Hong Kong, have been escaping the summer heat by taking ''refuge'' in air-conditioned working and living quarters. In fact, a recurrent infection or sinus problem was probably getting off lightly considering air-conditioning and the fungi that breed in them could cause a depressed immune system and even liver cancer, said Dr Vrijmoed, researcher and lecturer in the Department of Biology and Chemistry at the City Polytechnic of Hong Kong. Dr Vrijmoed is so nervous about the perils of air-conditioning (a contributing factor in sick building syndrome), which she describes as potentially life-threatening, she refuses to have the system piped into her office at City Polytechnic. ''Sorry about the heat in here, but if you knew what I did about what comes out of air-conditioners you would welcome this bit of discomfort,'' she said. After conducting research in Hong Kong and collating this information with findings of official studies done in Canada and the United States, Dr Vrijmoed has shocking news about the ubiquitous air-conditioners used at home, in public transport, in offices, in restaurants, in shops - practically everywhere in Hong Kong. ''In Hong Kong we certainly have all the same fungi that have been identified in overseas studies, but probably many more species here considering this is a sub-tropical country,'' she said. ''The problem is air-conditioners are excellent breeding places for fungi. There are dozens of species of fungi that do grow in air-conditioners, but I've found three or four dominant strains present in the office systems I've investigated here. ''Some are poisonous, others are allergens [which cause allergies], some are immuno-suppressants [lower resistance to infections], and others are aflatoxins [cause liver cancer].'' She said some of the ailments caused by the fungi included flu-like symptoms such as a runny nose, sore throat, aching body, fever and so on; allergies like asthma and hay fever; headaches, malaise and a general feeling of being under the weather. ''It has also been proved a certain type of fungi can cause liver cancer,'' she said. ''A study was done in Denmark where workers in a catering business had developed liver cancer and it had nothing to do with their job. Eventually aflatoxins in the air-conditioning were identified,'' Dr Vrijmoed said. Strangely enough, Legionnaire's disease - a serious form of pneumonia affecting the lower lungs caused by a bacteria disseminated by air-conditioning - does not appear to be a problem in Hong Kong. This is partly because air-conditioning systems are treated with biocides which kill the host organisms. Doctors are, however, not bound to report cases. Between 1983 and 1991 less than 10 cases of Legionnaire's disease were confirmed in the territory, but none had been officially reported since then. Dr Vrijmoed said it was impossible to gauge the extent of the problems air-conditioning caused in Hong Kong. ''This is because no official studies have been done. I have done tests from a scientific point of view, but they have not been done in conjunction with the necessary medical studies.'' To Dr Vrijmoed's dismay no official or Government appointed study of pollution in air-conditioning have been done in Hong Kong - which means no standard safety levels have been set. ''We don't know the extent of the problem, but it's widespread. Just one of the air-sample tests I did at a local office showed 9,000 fungal spores per cubic metre of air, which is absolutely unacceptable.'' Dr Vrijmoed said fungi needed moisture, food and a comfortable temperature in which to grow, requirements which were more than adequately met in offices. ''In most offices the air-conditioning is turned off at night which causes condensation and thus water for the fungus. The air is full of nutrients in the form of hair, scales of skin, bits of nail, dust and other bits and pieces, and temperature is no problem.'' Dr Vrijmoed said the ''Monday blues'' syndrome or ''Mondayitis'' was not a figment of the imagination. ''Just imagine, most office air-conditioners are turned off for the weekend: fungal spores, which multiply by the millions, germinate happily all weekend and then get blown out on Monday morning in their trillions. No wonder allergies and other symptoms are worse for the first half of the day,'' she said. What can be done about it? ''The Government is completely neglecting the indoor environment and should urgently look into air-conditioning as part of the sick-building syndrome,'' she said. The Government's Environmental Protection Department was vague about the issue, referring queries to the Electrical and Mechanical Services Department. After many more referrals within the department, senior building services engineer, Lau Kwok-fan, was able to throw some light on the matter. ''The public should not think we are ignoring the problems of air-conditioning. We are looking into the problem at the moment, but because of limited resources and staff we are only conducting our studies in Government buildings [such as the Legislative Council chambers],'' he said. ''We are measuring indoor air pollutants and collating this data. We are also teaching staff how to clean air-conditioning units and ducts. ''The Government is definitely not being passive. We want everybody to lead a healthy life and we realise air-conditioning is a vital part of life in Hong Kong so it is a priority. Once we have enough information, we will be able to prepare some sort of yardstick or standard for the useage of air-conditioning.'' Mr Lau could give no indication of when this might happen. Other than putting pressure on the Government to take notice and to remind company managements to monitor the air system and regularly clean the air-conditioning filters, Dr Vrijmoed said there was little the individual could do to control the office air-conditioner. She did, however, offer some housekeeping tips for making home air-conditioners safer. ''Clean the filters at least once a week. Run de-humidifiers to make sure the air is as dry as possible and prevent water from collecting in the unit. ''Let's face it, air-conditioning is a problem. The less you use it the better. The air outdoors may be polluted, but from a microbial point of view it's safer than being in air-conditioning.''