minimal lethal oxygen concentration

例句：

1. 1. Theair quality in this area is criticallylow, with a minimal lethal oxygenconcentration of less than 10%.
   这个地区的空气质量非常低，氧气浓度不足10%。
2. 2. Dueto the high altitude and thinair, the minimal lethal oxygenconcentration for breathing is very low.
   由于高海拔和稀薄的空气，呼吸的最小致死氧浓度非常低。
3. 3. In order to ensuresafety during emergency evacuation, it's crucial to maintain aminimal lethal oxygen concentration above 18%.
   为了确保紧急疏散期间的安全，必须保持氧气浓度在18%以上。