I have the same problem and haven't been able to fix it. However, others have had the same problem and have posted their solutions. The sizzling sound is caused by electrical arching between the plates and one or both of the two tungsten wires that are run parallel to the plates (if you turn off all the lights and wait for your eyes to adjust to the dark before turning on the Ionic Breeze, it's a pretty cool light show!) Here are things found by others to cause the arching and what they did to fix the problem:

• --dirt, lint, or tiny hairs stuck somewhere (usually towards the top or bottom of the plates or wire, and maybe in the grid contact points). Clean it better. Using canned air can help blow out the problem.
• --water droplets. Make certain there is no moisture anywhere when you put the grid (plates) back in. Using canned air can help dry hard to reach areas.
• --burn marks or melted plastic. These indicates a short circuit. Says dnewcombe1: "There is a feeler bracket that guides the two rear thin wires while the cartridge is being inserted. This "feeler" can melt and become disarranged." You can't fix this issue.
• --build up on the ionizing wires. Clean them. It's hard. I took mine apart and used steel wool.