Prince, the problem is that the stuff that's doing the most damage is microscopic and measuring equipment is expensive. From the many tests I have had done I can tell you that a) if you have any windows open even the IQ can't keep up and will only reduce the particles by around 10%, the only way to have clean air is to keep the machine running 24/7 b) on bad days, which is now more than 30% of the time the air in the larger rooms of your flat will still be above WHO levels, only small rooms that are shut will be clean.
Today and yesterday the particle readings were 1.1 million and 770,000 respectively, the WHO limit is 60,000, this is in the middle of summer !!
These readings were backed up by the Headley index.
You are doing yourself and/or your family irreparable damage, get out of there.