Is Beijing affected by the the nuclear radiation in Japan?

My family(2 adults and 2 kids ages 6 & 10) will be traveling to Beijing this coming April 3-11 but I'm having second thoughts whether to go or let go of our trip because I'm worried about the current situation in Japan. China is among the countries closest to Japan. Are the people in Beijing alarmed that they might get affected by the nuclear radiation in Japan? Please advise. Thank you very much.