The Airparif monitoring agency said smog density was still near alertlevels Monday, but rain forecast for Tuesday was expected to clear the air.
空气监测机构表示，周一雾霾浓度仍然处于警戒水平，但是预计周二的降雨能够净化空气。
2
Similarly, tests with multiple stages can be classified into the three OOT alertlevels, but this task is much more challenging and less straightforward.
同样，多阶段检测也可分为三种OOT警戒水平，但是这项任务太具有挑战性，不是那么简单。
3
Their implementation will help to build and strengthen effective mechanisms for outbreak alert and response at national and international levels.