Sorry, this is a correct statement:

Always wear an N95 particulate respirator when cutting CCA pressure-treated lumber.

But not for the reason you may think. While you certainly want to avoid ingesting or breathing the chemicals in pressure-treated lumber, you really want to avoid inhaling the sawdust from any lumber. Over time, fine sawdust can do some serious damage to your lungs. Always wear a respirator when cutting or sanding wood.