Almond Douglas V. author Columbia University. International and Public Affairs Columbia University. Economics Edlund Lena author Columbia University. Economics Palme Marten author Columbia University. Economics contributor originator text Working papers New York Department of Economics, Columbia University 2007 Japanese atomic bomb survivors irradiated 8-25 weeks after ovulation subsequently suffered reduced IQ [Otake and Schull, 1998]. Whether these findings generalize to low doses (less than 10 mGy) has not been established. This paper exploits the natural experiment generated by the Chernobyl nuclear accident in April 1986, which caused a spike in radiation levels in Sweden. In a comprehensive data set of 562,637 Swedes born 1983-1988, we find the cohort in utero during the Chernobyl accident had worse school outcomes than adjacent birth cohorts, and this deterioration was largest for those exposed approximately 8-25 weeks post conception. Moreover, we find larger damage among students born in regions that received more fallout: students from the eight most affected municipalities were 3.6 percentage points less likely to qualify to high school as a result of the fallout. Our findings suggest that fetal exposure to ionizing radiation damages cognitive ability at radiation levels previously considered safe. Demography Environmental studies Education 0607-19 http://hdl.handle.net/10022/AC:P:429 English NNC NNC 2011-03-28 10:46:26 -0400 2011-06-22 15:31:35 -0400 3349 eng