The nose, pharynx, larynx, trachea and bronchi all work like a system of pipes through which the air is funnelled down into our lungs. There, in very small air sacs called alveoli, oxygen is brought into the bloodstream and carbon dioxide is pushed from the blood out into the air.
And, just to clarify, the kitty litter in your trunk, to be used for traction, needs to be taken out and spread around your tires. Most cars are front wheel drive, so the extra weight alone in the back ain't gonna do you much good.
You might go for conventional cat litter, a known brand like Tidy Cats, for example. Many pet owners prefer scoopable kitty litter, which clumps when wet for easy disposal of all kinds of waste. Your concern may also be to control odor.