"U.S. Pollution: Made in China" "The first high-resolution analysis of smog traveling across the Pacific reveals that the contribution of Asian smog to pollution in U.S cities is higher than previously thought."
The radiation from the Fukushima Japanese nuclear crisis reaching California, even at the highest point, did not even register above a fraction of natural "background" radiation. That's right, did you know there is natural radiation? From the sun and from the earth, all living things benefit from small levels of radiation.
Meanwhile, real pollution from China contributes over 20% to the ozone in American cities. "What is more, on days when ozone levels in U.S. cities were higher than the maximum, Asian emissions pushed them over their safety limits more than half the time."