The air conditioner, which is kept on round the clock, could be a health hazard, especially for people with respiratory problems or who are suffering from the seasonal cold and cough, for them the air conditioner is more a bane than a boon.
If the AC is not always properly cleaned it can be a safe place for the bacterium to breed and get emitted inside the rooms. People who even get it cleaned lament about the maintenance companies who often do the bare minimum, not even checking for mould, with which they would not be able to deal anyway.
Vast majority of respiratory problems are due to dusty and rusty ACs and can be controlled by destroying invisible contaminants and micro-organisms in indoor air and contaminated ventilation systems.
It is better to get air conditioners very properly cleaned including the ventilation system, the air ducts, evaporator coils, drainage trays and pipes, registers, grills and air plenium, and then air-disinfectant should be sprayed. The reason being is that pollen grains and dust particles build up and get caught in the filters and when you put the blower on it disperses the things caught in the filter into the air.
In fact there's a deadly disease called Legionnaire's disease which is caused by poorly maintained ACs. Legionnaires' disease, also known as "Legion Fever" is the more severe form of the infection and produces high fever and pneumonia. Potential sources of such contaminated water include cooling systems.
