Ground-level O3 pollution and its impacts on food crops in China: A review

Ground-level ozone (O-3) pollution has become one of the top environmental issues in China, especially in those economically vibrant and densely populated regions. In this paper, we reviewed studies on the O-3 concentration observation and O-3 effects on food crops throughout China. Data from 118 O-3 monitoring sites reported in the literature show that the variability of O-3 concentration is a function of geographic location. The impacts of O-3 on food crops (wheat and rice) were studied at five sites, equipped with Open Top Chamber or O-3-FACE (free-air O-3 concentration enrichment) system. Based on exposure concentration and stomatal O-3 flux response relationships obtained from the O-3-FACE experimental results in China, we found that throughout China current and future O-3 levels induce wheat yield loss by 6.4-14.9% and 14.8-23.0% respectively. Some policies to reduce ozone pollution and impacts are suggested. (C) 2015 Elsevier Ltd. All rights reserved.