Respiratory dust content in air i creases with raising of dust concentration.

说明空气中呼吸性粉尘的含量随着粉尘浓度的增高而增加。

The dust concentration must be under control, and the dust collecting system efficiency must be fairly high.

控制粉尘浓度，要求集尘器系统效率良好。

The seam water injection is an effective measure to control coal dust concentration.

煤层注水是降低矿井粉尘浓度的有效措施之一.

The results show that the TIM increases with the decrease of dust concentration and the increase of spray-air pressure and dust particle size.

结果表明，最低着火温度随煤粉质量浓度的减小而升高，随喷吹压力和煤粉粒度的增大而升高。

Sublevel Mechanized caving method shows the characteristics of high out-put, more dust sources, high dust concentration and difficult to control.

煤矿综采放顶煤工作面开采强度大、产尘尘源多、粉尘浓度高，因而对尘毒的治理难度大。

So it is very necessary and emergency to monitor and test the dust concentration and granularity.

因而对其中所含粉尘的浓度及粒度进行监测是非常必要的.

In addition, the spray layer is thin and uniform, the construction speed is quick, and the resilience rate, the dust concentration and the cost are low.

且喷层厚度薄而均匀；施工速度快，回弹率低，粉尘浓度小，成本低。