How to change temporary directory for pg_dump?

I'm running out of space from my hard drive which has a 18GB PostgreSQL database. When I try pg_dump to a different drive, PostgreSQL creates temporary files on the disk it's dumping from, so I run out of space and the dump fails. This is the command I used: ~~~sh pg_dump -U myusername 'database' --format=tar > /anotherdrive/filetodump.tar ~~~ It eats free space the same way as with gzip. I tried this from Stackoverflow and a small file is created in the new directory, but nothing else, and pg_dump still writes to the original disk. How do I change temp directory for pg_dump? Note: My work_mem setting is pretty high already, I can't change that. My db version is 9.0.13.