Mark Critz (D), a top aide to the late Rep. John Murtha (D), and businessman Tim Burns (R) began airing their first campaign ads last week as the TV air war began in earnest in the May 18 special election to replace the longtime Congressman.

Critz mentions his late boss several times in his first spot, which is airing on cable and broadcast stations in the district.

Burns’ first ad, “Storyville,” is a biographical ad showcasing his roots in the southwestern 12th district.

Burns plays up his social conservative credentials by emphasizing his faith, anti-abortion-rights and pro-gun stances in the 30-second spot, which does not mention his party affiliation.

Critz is favored in the special election because the special election is being held on the same day as statewide primaries and Democratic turnout is expected to be particularly high because of a contested gubernatorial race.

Critz and Burns are running in both the special election and in the regularly scheduled Democratic primary that will decide the party’s nominee for the November ballot on May 18.