 |
| |||
| 10 particles 0. 3μm in size per cubic foot of air | |||
| |||
| 1 particle 0.3μm in size per cubic foot of air | |||
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| 100 particles 0. 3μm in size per cubic foot of air | |||
| 级净化: 11 phrases in 7 subjects |
| Drilling | 1 |
| Ecology | 1 |
| Explosives and Explosive Ordnance Disposal | 1 |
| Metallurgy | 2 |
| Shipbuilding | 2 |
| Technology | 3 |
| Textile industry | 1 |