DB2 LUW: Should temporary tablespaces share bufferpools with other tablespaces?
First of all, you must have a bufferpool that matches the page size of the tablespace. By that token if the temporary tablespace is the only one with the 32K page size then it will have the bufferpool for its exclusive use.

If you have other tablespaces with the 32K page size, only monitoring the system performance will tell you if there may be a benefit from a separate temp space bufferpool. 

You can use select * from sysibmadm.mon_bp_utilization to look at the bufferpool hit ratios and select * from table (mon_get_bufferpool(NULL,NULL)) to check page cleaner activity (POOL_NO_VICTIM_BUFFER and POOL_DRTY_PG_STEAL_CLNS should ideally be 0). If you see that a drop in the bufferpool hit ratio or high dirty page contention coincides with the temporary space use (a spike in POOL_TEMP_DATA_L_READS in select * from table (mon_get_tablespace(NULL,NULL))), creating a separate bufferpool of an appropriate size for the temporary tablespace in question might be useful.