The conservative blog Hot Air has been purchased by radio broadcaster Salem Communications, which adds the popular website to a stable that also includes Townhall.com and several right-leaning radio hosts.

In a statement obtained by POLITICO set to be released Thursday, Salem Vice President Jonathan Garthwaite explains that the purchase was made in hopes of creating one of the largest Web presences for conservative commentary.

Hot Air ranks as the seventh-largest conservative website over the past three months, according to rankings from the Web information company Alexa — though the rankings include Fox News, The Wall Street Journal and Drudge Report. Townhall, meanwhile, had the 12th-largest audience over the same time.

Hot Air was purchased from conservative commentator Michelle Malkin, who launched the site in 2006. Bloggers Ed Morrissey and Allahpundit have been the site’s mainstays and have built a wide audience within the conservative blogosphere.

“I have always respected Michelle Malkin and the insights and opinions presented by Hot Air,” said Garthwaite, who will serve as general manager of Townhall/Hot Air. “I look forward to working with Ed Morrissey and Allahpundit during a critical period in determining our country’s future.”

While the two sites will be operated under the same umbrella, they will remain separate entities, and both Morrissey and Allahpundit will stay on as the site’s bloggers, according to a source with knowledge of the deal.

Salem already has a significant presence in the conservative and Christian talk radio markets, broadcasting and syndicating the shows of Bill Bennett, Mike Gallagher, Hugh Hewitt and others.

The company owns 94 radio stations as well as a magazine and book publisher in the conservative and Christian markets.

Tom Perrault, senior vice president of Salem’s Web radio division, said, “The addition of Hot Air doubles the size of Salem’s expanding footprint in online conservative commentary.”

“Hot Air has experienced phenomenal growth — beyond our wildest expectations,” said Malkin in the statement. “With its established radio platform and fast-growing Internet brands, Salem is perfectly positioned to take Hot Air to the next level as a conservative multimedia powerhouse.”

Terms of the sale were not disclosed.