| Share | Phrase |
|---|
| 24.60% | purifying [purpose] device |
| 16.83% | purifying [purpose] system |
| 8.55% | purifying [purpose] performance |
| 8.39% | purifying [purpose] capability |
| 8.07% | purifying [purpose] efficiency |
| 5.44% | purifying [purpose] catalyst |
| 4.67% | purifying [purpose] apparatus |
| 4.67% | purifying [purpose] operation |
| 3.46% | purifying [purpose] fuel |
| 2.36% | purifying [purpose] ability |
| 2.19% | purifying [purpose] means |
| 2.16% | purifying [purpose] gas |
| 1.58% | purifying [purpose] function |
| 1.55% | purifying [purpose] passage |
| 1.22% | purifying [purpose] effect |
| 1.17% | purifying [purpose] oil |
| 1.17% | purifying [purpose] rate |
| 1.07% | purifying [purpose] unit |
| 0.78% | purifying [purpose] temperature |