Nowhere on that board do I see any ion producing voltage level "creators" with the components being seen.
Is there more to be seen, possibly hidden down inside the case elsewhere, like a HV transformer and its associative needle point electrodes / ion emitters.
Expecting a 2 or 3 connector cable / plug going to it from this board.
On this board shown, its being mostly its control and bells and whistles . .eg . . .LEDS + push buttons., maybe one small sized Sonalert alarm.
There is one logical T1-T2-G terminal marked Triac, which might be that HV transformers driver.
Just now re read all and caught . . . .
I have power going out of the yellow red and green wires to the fan and ionizer.
Then I might expect the yellow wire to be the ionizer feed.
So do the ionizer and fan work ?