Mysql Query issue using between

Mysql Query issue using between

I am trying to track inventory based only on install and removal dates and
report what is installed at any given day. Records that are still
installed, do not have a removal date. So I am trying to set the removal
date to Date(now()). But when I add between install_date and removal_date
it only finds records with both dates.
I have an inventory table which contains name, install_date and
removal_date and i have a master_date table which contains all dates from
2012-01-01 to 2014-12-31
Select inventory.name, inventory.install_date,
IFNULL(inventory.removal_date,DATE(NOW())) AS 'Removal Date',
master_date.date FROM inventory, master_date WHERE master_date.date
BETWEEN inventory.install_date AND inventory.removal_date
If I remove the between clause, it sets removal_date to NOW, but continues
to include records where the removal_date is prior to NOW. With the where
clause, it only returns records where removal_date is not null but the
date field is correct.
How can I use NOW in place of a NULL removal_date and return the correct
records?