Italian officials concerned about effect on pollution on The Last Supper

Milan, Italy is one of Western Europe's most polluted city, and art historians fear for the survival of Leonard daVinci's Last Supper located on a wall of the refectory of Santa Maria Delle Grazie Church.

Despite a state-of-the art heating, ventilation, and air conditioning system, officials feel they need to sample air quality to determine if air pollution - or visitors - might be destructive to the fresco.