SHORELINE, Wash. -- Garrett Thompson is waiting for a train, but he's not going anywhere. As a line of empty freight cars approaches, Thompson moves to an air pollution monitor on the pedestrian overpass near Richmond Beach State Park and begins recording spikes in soot and dust as the train rumbles by. While he's primarily looking for coal haulers, even empty trains are helping build a database aimed at assessing a link between airborne particulates and coal trains. Thompson is playing a small part in what is quickly becoming one of the most significant questions facing the Northwest -- whether to export millions of tons of coal from at least five port facilities proposed along the Pacific Coast and Columbia River in Washington and Oregon. Go to story #1