 |
| air cleaning: 61 phrases in 23 subjects |
| Agriculture | 1 |
| Agronomy | 1 |
| Automobiles | 1 |
| Construction | 5 |
| Drilling | 2 |
| Ecology | 7 |
| Electrical engineering | 1 |
| Electronics | 2 |
| Energy industry | 6 |
| Makarov | 7 |
| Metallurgy | 1 |
| Microelectronics | 1 |
| Mining | 2 |
| Natural resourses and wildlife conservation | 2 |
| Nautical | 2 |
| Nuclear and fusion power | 1 |
| Nuclear physics | 3 |
| Oil / petroleum | 2 |
| Oil and gas | 2 |
| Oilfields | 1 |
| Polygraphy | 1 |
| Technology | 8 |
| Transport | 2 |