Since the most hazardous fallout particles are the heaviest, they sink through the air and collect on streets and rooftops, making ideal shelters underground or in the middle of high-rise buildings.

因为在这之后会有最危险的也是最重的放射性颗粒，他们在空中下沉，聚集到街道、屋顶，所以理想的避难所是在地下室或者高层建筑的中间位置。