Conditioning air for human use

In an air-conditioning system comprising:

• means for passing a stream of air containing oxidizable pollutants along a path through a conditioning station, an ozonating station, a filter station downstream of the ozonating station, and a testing station downstream of the filter station and then introducing the stream into a living space;
• means in the path and in the conditioning station for conditioning the air stream with respect to its temperature and/or humidity;
• means in the ozonating station for at least periodically adding ozone to the air stream to oxidize the pollutants in the stream;
• means in the filter station for decomposing the added ozone to stable oxygen;
• and
• means in the testing station including a downstream sensor for detecting the ozone concentration in the stream and at least partially shutting down the system when the detected ozone concentration exceeds a predetermined safety threshold;,
• the improvement comprising:
• means including an upstream sensor upstream of the ozonating station for detecting the concentration of pollutants in the stream;
• control means connected to the ozone-adding means and to the upstream sensor for adjusting the amount of ozone added to the stream in the ozonating station so that it just corresponds to the amount needed to oxidize the pollutants detected and does not substantially exceed this amount needed to oxidize the pollutants;
• and
• means for periodically injecting into the stream at an injection location downstream of the filter station and upstream of the testing station a quantity of ozone sufficient to raise the ozone concentration in the gas stream above a predetermined detectable threshold level detectable by the downstream sensor and insufficient to raise the ozone concentration in the gas stream above the predetermined safety threshold, whereby the downstream sensor is periodically tested.