Using TRIM for an ALIAS

I want to TRIM the rows of my output, but I have aliases for each field name. How do I use TRIM with aliases?

i.e.

SELECT /*csv*/ DISTINCT

(CASE WHEN (ACCT.OWNCD = 'S') THEN 'P' WHEN ((ACCT.OWNCD = 'JO') OR (ACCT.OWNCD = 'JA')) THEN 'J' ELSE ACCT.OWNCD END) AS "Member Type",

VIEWPERSTAXID.TAXID AS "SSN",

ACCT.MEMBERAGREENBR AS "MEMID",

PERS.FIRSTNAME AS "First Name",

PERS.MDLNAME AS "Middle Name",

PERS.LASTNAME AS "Last Name",

PERS.SUFFIX AS "Suffix",

PERS.DATEBIRTH AS "DOB", ADDRLINE.TEXT AS "Address Line 1",

'' AS "Address Line 2"

Should TRIM be used to set the CHAR limit or should I just qualify that before the SELECT in the SQL*PLUS syntax portion of the script?