Retail experts say about one-third of Atlanta’s roughly 17 malls are thriving, while another third is struggling. The declining health of Atlanta’s malls could pose a threat for metro Atlanta’s $12 billion hospitality industry. Visitors to the area spent more than $1.7 billion in 2012, according to the Atlanta Convention and Visitors Bureau. “The malls that are surviving here are the ones in affluent areas,” said Ellen Dunham-Jones, a professor of architecture and urban design at Georgia Tech, who studies dead malls and mall redevelopment.