| Share | Phrase |
|---|
| 42.37% | harmful [producing effect] component |
| 12.95% | harmful [producing effect] emission |
| 8.47% | harmful [producing effect] gas |
| 4.85% | harmful [producing effect] substance |
| 4.19% | harmful [producing effect] hc |
| 2.91% | harmful [producing effect] effect |
| 2.66% | harmful [producing effect] product |
| 2.47% | harmful [producing effect] compound |
| 2.42% | harmful [producing effect] pollutant |
| 1.95% | harmful [producing effect] deposit |
| 1.88% | harmful [producing effect] constituent |
| 1.67% | harmful [producing effect] influence |
| 1.45% | harmful [producing effect] material |
| 1.45% | harmful [producing effect] content |
| 1.39% | harmful [producing effect] co |
| 1.39% | harmful [producing effect] contaminant |
| 1.11% | harmful [producing effect] oxide |
| 0.97% | harmful [producing effect] nox |
| 0.72% | harmful to environment |
| 0.72% | harmful [producing effect] hydrocarbon |
| 0.72% | harmful [producing effect] matter |
| 0.62% | harmful [producing effect] element |
| 0.36% | harmful to engine |
| 0.17% | less [degree] harmful |