Hank Aaron: Chasing the Dream (TBS, 8:05 p.m. -- 10:05 p.m.): It was a big enough step for 18-year-old Hank Aaron when his minor-league contract was purchased by the Boston Braves in 1952. It had only been five years since Jackie Robinson had broken major-league baseball's color barrier by joining the Brooklyn Dodgers in what the team's boss, Branch Rickey, called ''the great experiment.''
But as shown in this massive new documentary, the real trouble started in the 1974 season when Aaron -- by then his team was the Atlanta Braves -- started closing in on Babe Ruth's career home-run record of 714. Aaron received death threats and hate mail from racists aghast at the prospect of a black man beating out the Babe.
The program details the obstacles faced by Aaron during his career as it paints a picture of the sport and the society it operated in. Baseball highlights are mixed with interviews with baseball greats like Willie Mays and Reggie Jackson, as well as with social and political figures.
The Search for Clean Air (PBS, 10-11 p.m.): It's safe to call this show's approach to air pollution the long view: At one point it cites ordinances passed by England's Edward I in 1306 -- more than 500 years before the Industrial Revolution.
Hosted by Walter Cronkite, who brings his gravitas to many science-related shows these days, the documentary also reviews the recent history of the much-debated issue, chronicling a series of events over the past several decades that led to the array of laws governing how we treat the air around us today.
The real focus is the present predicament, in which experts -- as the program makes clear -- can disagree as to causes. Robert Ian Bruck of North Carolina State University concludes that air pollution is what's killing trees on Mount Mitchell. William Sommers, head of the United States Forest Service's studies on air pollution and forest decline, says we can't be sure of that.
Please check local listings for these programs.