But staffrooms and classrooms, like offices, can be unhealthy places for the teachers who work in them. Sick building syndrome was recognised by the World Health Organisation as far back as 1982. And more recent studies carried out in the UK, Sweden and the United States have shown that working in a poor environment can cause symptoms such as lethargy, stuffy or runny nose, dry throat, headaches, itching or dry eyes and even flu-like symptoms.
But in all probability, teachers with any of these low-grade symptoms associated with environmental stress are likely to soldier on regardless.
Sally James is a language support teacher in a secondary school in Leeds."I often have what I would describe as a bad cold - runny nose and a general bunged-up feeling. Last winter, as soon as I managed to shake off one virus, another one started. The only time the symptoms cleared up was during the holidays.
"I came back after New Year feeling on top of things, only to go down with a bug by the end of the first week of term. It's never bad enough to take a day off. I tend to carry on because I know that I'll recover during the holidays. "
Various explanations have been put forward by experts and researchers. One theory is that electromagnetic radiation from new technology, overhead powerlines and radio masts is to blame. Another suggests that air-conditioning, poor ventilation, unhygienic workplaces or chemicals in paints and cleaning solutions could be the culprits.
Canadian psychologist Jimmy Scott believes that many of the physical and psychological difficulties people suffer are the result of energy imbalances caused by electromagnetic pollution.
"In every large city," he explains, "there are thousands of radios, TV sets and satellite receiver dishes. The combined strength of their electromagnetic fields is enormous and it messes up your system. Take people who think they suffer from an allergy. They don't. What they do have is a severe imbalance in their electromagnetic body system which causes over-sensitivity to many components of everyday life."
The US Environmental Protection Agency has established that the combined presence of some the following features is most likely to cause sick building syndrome:
* indoor air pollution - tobacco smoke, asbestos, formaldehyde, pollutants from carpets, air fresheners, paints, adhesives, photocopiers, print rooms, pesticides; * poor ventilation systems - inadequate maintenance, bad design, incorrect positioning of air vents; * inappropriate use of the building - air recirculated or poor design during conversion to a new use.
Bertil G Johnson is an expert on planning and building. He was the principal adviser for a World Health Organisation report on sick building syndrome, published in 1995. WHO research in Swedish schools and kindergartens showed that either the building or the geographical location of the school could affect the health of staff and children alike. Of 67 kindergartens surveyed, only one met the requirements for an effective ventilation system.
One elementary school in southern Sweden was surveyed because there were complaints about stale air and a bad smell, particularly in cold weather, when heated air was recycled. One teacher and one pupil were forced to move to different schools because of severe allergic reactions. Another teacher suffered more frequent asthma attacks at school. Many teachers and pupils complained about tiredness.
Further investigations showed that because the school had been built on a slightly waterlogged site that needed extensive filling, mould had grown on timber left in the foundations. The smell of the mould was coming up from the foundations through a vent. Changes in the ventilation system improved the situation.
Here in the UK, workers at the former DHSS headquarters in south London constantly complained of sore throats which they said were caused by sick building syndrome. After the department moved out, the tower block, which had been designed by modernist architect Erno Goldfinger, was converted into luxury flats.
Roger Coghill, an independent researcher into environmental pollution, says there may be other causes for what look like stress-related symptoms. "Everyday items such as fluorescent lights, mobile phones, TVs, even digital watches, are potentially harmful to the immune system," he says. There is also concern that radar station transmitters emit waves powerful enough to affect the health of those who live and work nearby.
Parents in California have formed a group called FACTS (Families Against Cellular Towers at Schools) because of their fears about the siting of cellular phone towers in school grounds. Although the US Food and Drug Administration does not know what the long-term effects of exposure to the towers will be, still the authorities have decided to reconsider their proposed developments.
As well as alerting teachers and others to the risks from unhealthy buildings, some researchers are trying to find out what makes for a healthy working environment. A project at NASA's Stennis Space Centre in Missouri, reported in The Daily Telegraph, found that humble pot plants could neutralise the effects of indoor pollutants.
So what does all this mean for the average teacher?
Statistically, the risk of ill health from environmental pollution or sick buildings is small. Researchers have found that the crucial factor in determining whether a building is making its inhabitants sick or not, is whether people feel they have control over their working environment.
The best advice would be that the next time that a stuffy, irritable feeling starts to overwhelm you, take a good look round your staffroom and classrooms to see where changes can be made.
TEN WAYS TO KEEP YOUR STAFFROOM AND CLASSROOM HEALTHY
* Bring in fresh flowers and pot plants to help keep the air clean * Prickly eyes or cold symptoms can be caused by central heating and double glazing. A bowl of water near a radiator can prevent this happening.Add a few drops of pine aromatherapy oil to counter the effects of stale air.
* Use an ioniser to charge the air with negative ions. It will produce a refreshing atmosphere rather like sea or mountain air.Details of stockists for ionisers and air purifiers are available from Bloomfields tel: 0181 800 2677.
* Open the windows as often as possible, even in winter and especially first thing in the morning and after lunch.
* Keep a selection of drinks, juices and water available in the staffroom.Make sure that the coffee making area is kept clean and disinfected regularly. Draw up a rota if necessary.
* Make sure that work areas have the right seating and desk height for comfortable working.
* Use screen guards on computers to reduce glare affecting the eyes.
* Take a 10-minute break each hour if you are working at a computer for long periods.
* Make sure that there are pictures or posters decorating the walls in the staffroom, as well as on display in the corridors and classrooms.
* Store away files, books and papers in cupboards and filing cabinets to avoid dust building up. Have regular clear-out sessions to avoid clutter.
* Wear natural fibres such as cotton, linen, silk, wool and leather to reduce the chance of static electricity building up.
* Volunteer for playground duty as often as possible. It gets you out of the building for a good dose of fresh air.
COMMON INDOOR POLLUTANTS
* Formaldehyde: irritates nose and throat; can cause headaches and trigger asthma; found in chipboard and plywood, carpets and furnishings, paint and tobacco smoke - neutralise with spider plants.
* Benzene: can cause dizziness andweakness - found in paint, cleaning solvents, plastics and polishes - neutralise with chrysanthemum plants in garden pots.
PLACES TO WATCH OUT FOR
If you work in a computer room, a science laboratory or a portakabin where there are portable gas heaters in winter, it pays to give special attention to your working environment.
Check that there is:
* adequate ventilation * the right seating to promote good posture * protection against IT or chemical and electrical hazards * enough time to take adequate breaks.