What's wrong with aircon
In the broader environmental scheme of things, it’s best not to use air conditioning: it uses energy, and contributes to pollution and global warming. However, as regards immediate human health issues, the argument against air-con is somewhat harder to make.
Many studies over the past two decades, and several reviews of research over this period, have found that occupants of office buildings with air-con report, on average, more symptoms than workers in buildings with natural ventilation.
The symptoms tend to be quite a mixed bag, from headaches and dizziness to various respiratory-tract irritations, and are seldom linked to a specific cause. This phenomenon is often referred to as ‘sick building syndrome’. In addition to faulty or dirty air-con systems, various chemicals that occur in indoor office environments may contribute to the problem.
Probably the most common and likely contaminants in air-con systems are mold spores, from mold growing in damp, poorly maintained systems. Some people, often those who already have asthma or allergies, are much more susceptible to 'sick building syndrome' than others.
It is possible for infectious viral and bacterial diseases to be spread by air conditioning units, but such cases are quite rare – or at least not well documented. You are much more likely to get an infection by touching a contaminated surface and then touching your facial area (without a good hand-wash first).
Aircon has its uses
To give it its due, air conditioning significantly decreases the risk for heat-related illness (e.g. heat stroke), particularly among vulnerable groups like the elderly – and children.
And, all-in-all, a properly installed, WELL-MAINTAINED (note caps!) air conditioning system is in fact unlikely to put the kids’ health at serious risk.
Other ways to beat the heat
But to my mind, the first choice would be to try to find other ways to keep classrooms cool: fans, opening doors and windows, using light-coloured window blinds, instituting a nap time during the hottest part of the day, etc. It's also quite feasible to monitor children in the summer months to make sure they don't get overheated and dehydrated.
If the decision is made to go with air-con, then aim to use it conservatively – i.e. just to take the edge off the hottest days, when the heat really interferes with the children’s basic comfort levels and concentration. Indoor summer temperatures shouldn't be allowed to go much above 26°C.
It is also be valuable to keep a record of any 'sick building'-type symptoms the children may develop, especially if these seem worse when they are at school.
– Olivia Rose-Innes, EnviroHealth Expert, Health24, October 2006