All conditions can be temporary, persistent, or permanent. The manner of inflicting it will specify if its not temporary - for example, environmental effects are persistent, and some monster powers may be permanent (a gorgon turning you to stone would be a permanent effect).
Whatever causes it will specify which it is. If it says nothing, then it's temporary.
No attribute can drop below 1. Conditions don't reduce attributes, though, they apply a die penalty to attribute checks related to that attribute. So when bleeding, your END stays the same; but you suffer -xd6 when making END checks. Your HEALTH isn't the result of an attribute check, so it is not affected by a die penalty.