Just thought I would post this from personal experience. For a while on and off now I have had wheezing and coughing. Not anything wrong with me though. Seen a few doctors over it and use alot of decongestion meds and inhalers. My case is a little unique since I am away from home alot. I was in the US Marine Corp and deployments and now my job takes me over seas. When I am gone it goes away.

We had thought it was allergies. Turns out it was my kitty litter!!! Manufacture's blend silica in with clay. Silica has superior absorbent properties. Its the primary agent in the clumping action of litter. Well anyhow my doctor was talking to a lung guy about me and he told him to ask me what litter I use. He told him you would not believe how many people's lung issues are caused by having clay based litter in the house.

I used to use Tidy Cat litter. 20 pounds of it for under 10 bucks was a good deal, smelled good, clumped good. Anyway I looked into it some on the net and it was a worthy theory. If you look up Silica they tightly control production since its on par with stuff like asbestos. The government allows the use of it if you can prove there is no dust. In a lab it does show that but in practice its different. Everytime you change it, scoop, your cat uses it a nice micro cloud of silica dust gets shot out.

So I went and bit the bullet and bought "Worlds Best Cat litter" brand that they sell in the US. IT was 30 bucks for about 30lbs of it. Alot more expensive but the bag says it lasts 90 days and you really never have to change it if your cleaning it out daily.

Its made from 100% compressed crushed corn powder. So safe you or your animal could eat it and it just runs through you. Theres no added anything. The scented version use's lavender oil to scent it...100% naturally obtained.

Anyhow flash forward a couple weeks to today and not one respiratory issue. I wish I had known this before. I have bought 2 HEPA air filters, and put in expensive filters in my air duct system for my house which has helped but not perfect. No more clay based litter and all is well.

As a side note this brand has superior clumping, and can be flushed if you desired to. I have zero odor problems or issues with it breaking down. Included some links to the product. If you look it seems to be popular now to buy corn or compressed paper litter. Many other brands so I assume they probably work on the same level. Highly suggested if you to are suffering from coughing, wheezing at night but can not figure out what the deal is. Whatever money is spent more on it at least in my case will be made up in being able to sleep soundly, and not having to use perpetual decongestion medication or inhalers. I even bought a steam Vicks vapor thing to deal with this issue. All resolved now!

http://www.worldsbestcatlitter.com

http://www.amazon.com/391032-Clumping-L ... est+litter

Another similar, inexpensive option for cat litter as well is Chick Feed. Like what you would feed to baby chickens. That is what my bengal, Ramses uses since he was with the breeder. It is inexpensive, and will do no harm to your cat at all if he eats it. It also has a lot less odor than the regular cat litter, which i was quite surprised about. And per kg (or lb), it is cheaper than buying litter from the grocery store!
It's kind of amusing though, going to the local farm supplies store and asking for a bag of Medicated Chick Feed, oh, and can you please load it into the little blue sports car in the parking lot? :P

Hezz, I use something similar called Layer Crumble - it's another product traditionally used for chickens.
The breeder raised all her Bengals on it & our boy B'alam has used it for almost 2 years now with no issues.
It can sometimes be a little dusty when you get near the bottom of the bag but considering how cheap it is (about AU$1 per kg) I don't mind throwing away a bit when the bag is getting low.