Take the dog for a good long walk before you leave! 20 minutes at least play with him and when you get back give him a reward! The reward may be another walk if thats what he likes! This may take a lil time but you are in a tight spot with a dog in an apartment! You have to put the time in with a dog, make him feel fullfilled and not just fawned on but exersize him and work on training him
to make him feel part of whats going on !

~Stridar~

I only ever leave my puppy for an hour at the most. I play something soothing like Mozart on the stereo and leave him with one of those dog toys that you can fill with treats (I used mashed semi cooked chicken liver, cooked in extra virgin cocnut oil .. he loves that!!!!)

Distraction is a great tool :-)

.. and he can spend the time licking it out. And then he gets a big fuss (well, he always gets that) when I get back.

My neighbours tell me he never barks.

Barf blog: //www.curezone.org/blogs/f.asp?f=731

Find a holistic vet that can give you various herbs for calming, or for senility (since he's older). Bach flowers are a good idea too, they work more on the mental level which is probably where his problem lies. It can be very hard with an older pet however. There are also citronella no bark collars that spray a burst of citronella when they bark, it doesn't work for everyone but its worth a shot. Definitely find a holistic veterinarian!