Astudy on the establishment of environmental standard of photochemical oxidants for protecting plants

点击翻译按钮获取中文摘要

In the present study, we investigated the effects of ozone (O3), a major component of photochemical oxidants, on growth and yield of crops cultivating in the suburban areas of Japan and evaluated environmental standard for protecting plants. There was great difference in the sensitivity of growth and yield in O_3 among the crops cultivating in the suburban areas of Kanto-district of Japan. Based on the results of experimental study on the effects of O_3 on yield of crops, the most suitable O_3 parameter for evaluating the effects of O_3 on the yield of crops was considered to be AOT30 (accumulated dose over a threshold of 30 ppb of O_3). We propose 1.5 ppm h of AOT30 (9:00-16:00) as critical level of O_3 for protecting the yield of crops cultivating in the suburban areas of Japan. In most areas of Tokyo Metropolis and Saitama Prefecture, AOT30 of O_3 is above 1.5 ppm h from July to September. We evaluated O_3-induced yield reduction of 5 crops (komatsuna, quing-geng-cai, turnip, garland chrysanthemum and welsh onion) from July to September As a result, the O_3-induced reduction rate of the 5 crops was estimated to be 11-35% in the western part of Tokyo Metropolis and northern part of Saitama Prefecture where the concentration and dose of O_3 are relatively high. Therefore, we should establish environmental standard of photochemical oxidants for protecting plants as soon as possible.