Tracing airborne particles after Japan's nuclear plant explosion

The powerful Tohoku earthquake and consequent tsunami that occurred off the east coast of Japan on 11 March 2011 devastated dozens of coastal cities and towns, causing the loss of more than 15,000 lives and leaving close to 4000 people still missing. Although nuclear reactors at the Fukushima Daiichi Nuclear Power Plant, located on the Pacific coast, stopped their operation automatically upon the occurrence of the M_w 9.0 quake [Showstack, 2011], the cooling system for nuclear fuel broke down. From 12 to 16 March, vapor and hydrogen blasts destroyed the buildings that had contained the reactors, resulting in the release into the atmosphere of radioactive materials such as sulfur-35, iodine-131, cesium-134, and cesium-137, which collectively can cause harmful health effects such as tissue damage and increased risk of cancer (particularly in children), depending on dose. Most of those materials emitted from the power plant rained out onto the grounds within its vicinity and forced tens of thousands within a 20-kilometer radius to evacuate (residents to the northwest of the site within about 40 kilometers also were moved from their homes). Some of the radioactive materials were transported and then detected at such distant locations as North America and Europe, although the level of radiation dose was sufficiently low not to affect human health in any significant manner.