BRISTOL — Porter and Dave Knight of Bristol have watched their Fresh Air child grow for the past 9 years. This year will be the 10th summer 14-year-old Elijah Hedrington, of the Bronx, has visited the Knights. “He’s fit right into the family since the very beginning,” Knight said. Porter believes that hosting a Fresh Air child is just as eye-opening for her family as it has been for Elijah. “Having a Fresh Air child helps your family grow as much as it helps the child grow. They see things differently but so do you,” she said.