CANBERRA, Australia – Fire alarms have been sounding in high-rise buildings across downtown Sydney and Melbourne as dense smoke from distant wildfires confuse electronic sensors. Modern government office blocks in the Australian capital Canberra have been closed because the air inside is too dangerous for civil servants to breathe. The sun has glowed an eerie red behind a brown shrouded sky for weeks over Australian metropolitan areas that usually rank high in the world’s most livable cities indexes. It’s an unprecedented dilemma for Australians accustomed to blue skies and sunny days that has raised fears for the long-term health consequences if prolonged exposure to choking smoke becomes the new summer norm.