Democratic state Rep. Tina Orwall has learned a lot about ultrafine particles, tiny pollutants (800 times smaller than the thickness of an average strand of human hair). She spearheaded a recent study to find out how prevalent they are in her district, which includes one of the nation's busiest and fastest-growing airports. The results? They're very, very prevalent. She also talks about ongoing efforts to site a new or expanded regional airport to take some of the pressure off of SeaTac International, which is bursting at the seams.