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Concentrations of 10 ppm can be endured for only a few minutes and cause profuse lacrimation in all people .

10ppm的浓度，只需几分钟，就会使所有的人流泪不止。

It has a repulsive acidic odor that can usually be detected at or below a concentration of 5 ppm .

它有一种另人厌恶的酸味，在浓度为5ppm或以下可以察觉到。

Type I Diabetes mellitus usually starts from adolescent , whose morbidity rate is about 83 ppm and still increases .

I型糖尿病主要累及青少年，患病率万分之0.83，还在不断增长。

By chance , oryza sativa is a like aluminum plant , its optimum concentration is 30 ppm was observed .

意外观察到水稻是喜铝植物，最适浓度是30ppm。