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

Abstract

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. Overexposure to ozone compromises crop yields, yet accurate estimates of such impact in Asia have been hindered by limited empirical data. This study assesses relative yield losses of three main crops in Japan, China, and South Korea through O-3 exposure-response relationships based on monitoring data and experiment-based sensitivities.