Emotional First Aid in a Firehouse Culture
New York City Fire Dept begins effort to address mental health needs of its members in aftermath of Sept 11 terrorist attacks that caused deaths of 343 fellow firefighters; firefighters are undergoing mandatory physical examinations at which they are also being asked questions to assess their mental state; retired firefighters and other counselors are making rounds to firehouses to see if anyone wants to talk; Fire Dept's counseling unit is offering private meetings that can be privately arranged; Fire Dept officials say Police Dept's approach, ordering all employees to attend sessions on psychololgical distress, would not work in firehouse culture; hope quieter approach helps those who are suffering excessively from feelings of guilt, sorrow and anger; photo (M)