The Vatican may be forced to limit the number of visitors to the Sistine Chapel if its new air conditioning and air purification systems don’t significantly reduce pollution levels. The head of Vatican Museums, Antonio Paolucci says he’s confident the new system, which is expected to be operational at the end of 2014, will curb the dust, humidity and carbon dioxide that are dulling Michelangelo’s frescoed masterpiece. But if it doesn’t, he says he’ll be forced to impose the the limitations. Some 5.5 million people are expected to visit the Vatican Museums this year. During high season some 20,000 people a day enter the Sistine Chapel, which was last restored in the 1990s.