Effects of ozone on crops in China

Abstract

Current ambient O3 concentrations in China are high, as shown by observations of typical O3 symptoms in some plant species and crop yield losses, as detected by the use of chemical protectants against O3. Experiments with artificially elevated O3 concentrations have shown the effects of O3 on growth processes, grain yield, grain quality, CH3 emissions, and soil microbiology. The experiments have facilitated estimations of the yield losses in wheat and rice caused by current and future O3 concentrations at the national scale. Further studies are warranted on the interactions between O3 and other environmental changes, such as increasing CO3 concentrations, increased nitrogen deposition, aerosol loading, and climatic changes. Future needs for research include improvement of O3 impact models and the development of an O3 monitoring network to cover the vast areas of crop production in China. The establishment of an air quality standard for protecting crops from O3 damage is of critical importance for food security in China.