lerks get to wo. >> brangham: barney rubin, robin raphel, thanks very much. >> you're welcome. >> brangham stay with us. coming up the devos agenda. how the secretary of education views for-prit schools. and, a "brief but spectacular" take on the importance of traveling abroad. now, to another story about extreme weatheand its impact. wildfires have plagued northern california and the pacific northwest this year. in california alone, some 6,400e burned nearly 1.5 million acres. most destroy wildlands, but, as special correspondent cat wise reports, some urban areas are increasingly under threat. it's not only from the flames, as researchers are ting understand the risks from all that smoke and ash. >> reporter: last october, this was santa srosa california' coffey park neighborhood. today, nearly a year later, it looks like this. crews of busy construction e rebuilding hundred of homes. nail by nail, communities around the region are rising from te ash-- but the questions about what was in that ash, and in the air above, that could impact resen long after the rebuilding is done. on a recen