Analysis on the Development Status of Coal Mine Dust Disaster Prevention Technology in China

Table 1

Dust concentration in workplace air standard.

The content of free SiO2 in dust (%)	Maximum allowable concentration (mg/m^3)
	Total dust	Breathable dust
<10	10	3.5
10∼50	2	1
50∼80	2	0.5
≥80	2	0.3