IEQc6.1 - space type category

That depends on whether anyone works in the space. The definition requires one or more individuals to normally spend more than one hour per person per day on average seated or standing as they work. If there is a security guard (for example) that is assigned to work in the concourse it may meet the definition of a regularly occupied space, even if 99% of the occupants just pass through. The examples of regularly occupied spaces (here: http://www.usgbc.org/resources/examples-regularly-occupied-spaces-include-following) lists information desks, front desks and hotel lobbies as regularly occupied.

If the concourse is a regularly space,MUST it have a task lighting? In my opinion,the task lighting is not necessary because the ambient lighting is appropriate and enough.

You will have to provide task lighting for workstations such as information desks.