National Geographic : 2006 Feb
tear the Alps on the dotted line. Seventy-seven million tons of cargo move through the moun tains in an average year-furniture, chemicals, livestock, mineral water, automobiles. By 2020, some predict, trans-Alpine commercial transport will double. The mountains concentrate the fumes and noise from all these vehicles. The emissions are trapped in narrow valleys where the wind doesn't reli ably reach, and the upper layer of warmer air at night creates a cap to hold them down. Their carbon dioxide is a contributor to global warm ing. As for noise, the same principle that makes the deep notes of the alpenhorn resonate up and down a valley works just as well for the engines of big trucks. Their maddening buzz-saw whine can be muted horizontally by the sound barri ers that have been added to many highways, but there is no way to block the sound that the val ley walls echo and carry upward. "Noise you'd barely hear on the flatland at a distance of 400 meters carries up to 2,000 meters in the mountains," said Dr. Klaus Rhomberg of Doctors for the Environment in Innsbruck. This constant undernoise raises blood pressure, shreds nerves, may increase the risk of heart 112 NATIONAL GEOGRAPHIC * FEBRUARY 2006 attacks and strokes, and impairs children's abil ity to concentrate. Standing on a bluff above Sauze d'Oulx, one of the Olympic skiing venues in Italy, gave me a great view of the valley-or rather two halves of a valley bisected by the motorway snaking toward France via the Frejus Tunnel. I was more than 1,100 feet above the highway, and the noise of the truck traffic was just as grating, and possibly louder, than it had been all night a hundred yards away from my hotel window in Bardonecchia. Traffic is also tiresome. In Matrei, an Austrian village near the Brenner Pass, the narrow main street is always jammed with cars making a detour through town to avoid paying the motor way toll. "Our village is very nice, but sometimes you can't cross the road because car, car, car coming," said Inge Makkawi in careful English. She and her husband were sweeping up swarms of crimson rose petals and fallen blossoms from the driveway of their pension. "Of course trans port must be. We can't do without it. Do we want to go back to using a horse? Or carrying goods on our backs? I don't know. I don't know. You can't stop it."