How do you build a carbon filter?

In order to build a carbon filter, which is used to remove unwanted odors or fumes from the air, use an activated carbon mesh like those used in professional filters, a small roll of aluminum screen, a 4-inch ventilation end cap, a 4-inch duct connector piece and a roll of duct tape. All of these pieces can be easily obtained from a Home Depot or Lowe's home improvement store.