Distinguished Professor Lidia Morawska,  showed me a demonstration with 2 glass Sauerkraut jars.

We also have a CO2 meter. This is the CO2 concentration  in the office.

 

The gas we live in is invisable, the composites are invisible. The only time we see air ‘quality’ is when its really bad, such as smoke from bushfires and factory smog.

 

Both jars are sealed and look identical.

Open and read the contents of one with the CO2 monitor. One is the same as the office. 885.

 

The other is 5713.

Beforehand one of the jar had  2 human breathes exhaled into  it before sealing.

They contain totally different mixtures of  gas and we cannot tell which is which without measurement.

As Prof Morawska say’s you can see if the water is cloudy, and this means some form of water pollution or similarly for noise and light pollution, but air quality cannot been seen.