Kitty litter for asthmatic cat

I have a cat with SEVERE allergies and asthma.  We switched to Okocat in August and I loved it. But overnight my pet started having loud breathing- loud enough that I can hear her in another room.  She had a rhinoscopy and they found a lot of junk in her nose. She was breathing just fine and quietly for two weeks after the surgery. When we returned home and started using the litter again she began having breathing issues once again.  I have read that pine and cedar can be toxic to asthmatic cats. I also need to look back through records but my cat may be allergic to pine- I do not remember. In any case, I suspect the dust is entering her nose and becoming paste like -blocking her passages.  That said if Pine is toxic to cats the litter could be irritating her nasal passages.  she may need to go in for another rhinoscopy -2nd in 1 month

this is where I found the info - but have not found further studies.

http://www.felineasthma.org/triggers/

I have a cat with asthma the vet suggested i use a pellet or crystal type litter. We tried it she wouldn't use it so the vet told me use what she will use but leave the lid off so when she scratches the dust disperses around her instead of getting trapped with her under the litter hood.  We have tried yesterdays news, chicken feed you name it. If it isn't good old fashioned clumping fresh step she flat out will not use the box sigh. 

My cat liked fresh step but every few years starts peeing outside the box. Remedied quickly by using potting soil or sand. Then transitioning back. Free4life brand makes a L'egere or sand grain which has also worked great

Mostly I am trying to see if anyone has had asthmatic cat w wood dust issues cause if rhinitis or other nasal blockages