Yeah, the problem is more pronounced in congested areas where the population density makes it hard to get out of the contaminated area quickly. Washing any (fallout) contamination from you body, and filtering your breathing air (even a simple surgical mask) is the first lines of defense. getting out of the contaminated area will best protect you from long term effects. If that isn't possible, reducing exposure to airborne contaminants is essential. plastic sheeting and wet sheets work well. Radioactive contamination is particulate contamination. Hose your house down and run your sprinklers until the water runs off into the storm sewers. not perfect, but better than being dosed daily with radiation.