In China, these levels were more than 4 tenths of a milligram between 1981 and 2001, according to Chinese government agencies; state media have reported even higher levels recently. Cities including Beijing recorded levels of more than 7 tenths of a milligram in January. These levels are around 10 times higher than U.S. levels measured in the 1990s, about 45 thousandths of a milligram.