The cat sneezes after you clean the house
If you notice that your cat sneezes every time you clean the house, then you should look into the products that you use, especially for cleaning the floors and areas that the cat comes in contact with.
The cat sneezes when your air freshener is on
Air fresheners can be toxic for cats and they are very dangerous for them. If you notice them sneezing, then stop using that type of air freshener altogether.
The cat sneezes when it sits on your clean linens or clothes
Clean clothes are a special treat, but if you notice that your cat often sneezes after having spent some cozy time on your clothes, then you should look into the detergent and fabric softener you use.