“Are You Smarter Than a 5th Grader?” (8 p.m., Fox): It’s back-to-school time all

“Are You Smarter Than a 5th Grader?” (8 p.m., Fox): It’s back-to-school time all over America, which means it’s also time for the sophomore season of “Are You Smarter Than a 5th Grader?” Jeff Foxworthy returns to host the game show that has adults struggling to make the grade and their kids getting the last laugh.

NFL Football (8:30 p.m., NBC): The Super Bowl champion Colts host the Saints from the RCA Dome in the opening game of the National Football League regular season.

“9/11’s Toxic Dust” (10 p.m., A&E): This new documentary focuses on the stories of four people who worked around Ground Zero and are now dealing with serious health issues. Also featured: interviews with experts who discuss how toxins in the air at “the pile” and lower Manhattan could have affected the body.

“Tim Gunn’s Guide to Style” (10 p.m., Bravo): The engaging man who seized our attention on “Project Runway” now has his own show and he’s out to help women look their absolute best. Aided by former model Veronica Webb, Gunn uses a tough-love approach as he leads fashion-challenged participants on an “emotional journey to unearth their personal style.” From wardrobe essentials and shopping tips to suggestions on finding the right fit, Gunn will attempt to arm them with the basics to make their own look polished and stunning. We’re confident that, somehow, he’ll find a way to make it work.