Directory Limits?

I have searched on Google but I just don’t seem to be finding the answer that I need.

Is there a way to limit the total size of files in a directory? I would like to limit the quota of a directory that users upload to... users are uploading to their own directory but I would like to limit the size of the directory to say, 2MB. Is there a way to do this with .ini or htaccess or is there another way to do this?