[anthrovolution]

There is no place that is 'safe', depending on the type and intensity of whichever calamity you are analyzing. Using polluted cities, such as Phoenix, Los Angeles, and others as a proxy for the contamination that might occur due to some sort of global conflict, two cities have been identified that appear safer than most. Using prevailing wind patterns and other climatological and meteorological data, along with air quality reports, those two cities are Salem Oregon, and Flagstaff Arizona. There are doubtless many more, but those are the two identified so far. This is not a highly scientific analysis, but is based on general data that can be gleaned from various websites on the Internet.