The League of Women Voters is launching a “seven-figure” TV ad campaign Friday in Massachusetts and Missouri to draw attention to votes cast this month by Sens. Scott Brown (R-Mass.) and Claire McCaskill (D-Mo.) regarding the reauthorization of the Clean Air Act.

Both Brown and McCaskill are up for re-election next year, and Roll Call Politics rates both of their races at this point as tossups.

The 30-second ads will run on network and cable TV in the two states beginning Friday night, and will be accompanied by a “six-figure” online campaign targeting in-state websites and social media outlets.

“Air pollution is a life or death issue,” Elisabeth MacNamara, national president of the League of Women Voters, said in a statement. “Senators Brown and McCaskill cast dangerous votes that put public health at risk.”

Both voted on April 6 for an amendment authored by Sen. Jay Rockefeller (D-W.Va.) to suspend any action by the Environmental Protection Agency under the Clean Air Act regarding carbon dioxide or methane for two years, except in respect to auto emissions.

Brown also voted to prohibit the EPA administrator from creating any regulation concerning greenhouse gas emissions to address climate change.

“When Scott Brown voted to eliminate clean air standards that reduce smokestack and tailpipe emissions, just imagine what it could’ve done to her,” the announcer says, as a young girl struggles to breathe while wearing a nebulizer.

A similar image appears in the Missouri ad, in which the announcer asks, “Shouldn’t Claire McCaskill protect the people — and not the polluters?”

The league is a nonpartisan political organization and has been a strong supporter of the Clean Air Act since its 1970 extension was enacted.

The Massachusetts ad: