And the first things that you can see from this graph is, if you look at the blue data points, which are the mechanically ventilated air, they're not simply a subset of the green data points, which are the outdoor air.
你可以明显的从这个图标中发现 如果你看一下蓝色的数据点 即代表机械通风系统的点 他们不仅仅是绿色数据点即代表着室外空气数据点 的一个简单的子集