Ozone pollution threatens the production of major staple crops in East Asia.

East Asia is a hotspot of surface ozone (O 3 ) pollution, which hinders crop growth and reduces yields. Here, we assess the relative yield loss in rice, wheat and maize due to O 3 by combining O 3 elevation experiments across Asia and air monitoring at about 3,000 locations in China, Japan and Korea. China shows the highest relative yield loss at 33%, 23% and 9% for wheat, rice and maize, respectively. The relative yield loss is much greater in hybrid than inbred rice, being close to that for wheat. Total O 3 -induced annual loss of crop production is estimated at US$63 billion. The large impact of O 3 on crop production urges us to take mitigation action for O 3 emission control and adaptive agronomic measures against the rising surface O 3 levels across East Asia.